firefox/mozilla-1623060.patch

diff -up firefox-74.0/widget/gtk/nsWaylandDisplay.cpp.mozilla-1623060 firefox-74.0/widget/gtk/nsWaylandDisplay.cpp
--- firefox-74.0/widget/gtk/nsWaylandDisplay.cpp.mozilla-1623060	2020-03-17 14:19:04.394231493 +0100
+++ firefox-74.0/widget/gtk/nsWaylandDisplay.cpp	2020-03-17 14:23:47.445480363 +0100
@@ -26,15 +26,12 @@ namespace widget {
 #define DMABUF_BASIC_PREF "widget.wayland_dmabuf_basic_compositor.enabled"
 // Enable dmabuf for WebGL backend
 #define DMABUF_WEBGL_PREF "widget.wayland_dmabuf_webgl.enabled"
-// See WindowSurfaceWayland::RenderingCacheMode for details.
-#define CACHE_MODE_PREF "widget.wayland_cache_mode"
 
 bool nsWaylandDisplay::sIsDMABufEnabled = false;
 int nsWaylandDisplay::sIsDMABufPrefTextState = false;
 int nsWaylandDisplay::sIsDMABufPrefBasicCompositorState = false;
 int nsWaylandDisplay::sIsDMABufPrefWebGLState = false;
 bool nsWaylandDisplay::sIsDMABufConfigured = false;
-int nsWaylandDisplay::sRenderingCacheModePref = -1;
 bool nsWaylandDisplay::sIsPrefLoaded = false;
 
 wl_display* WaylandDisplayGetWLDisplay(GdkDisplay* aGdkDisplay) {
@@ -423,7 +420,6 @@ nsWaylandDisplay::nsWaylandDisplay(wl_di
       sIsDMABufPrefBasicCompositorState =
           Preferences::GetBool(DMABUF_BASIC_PREF, false);
       sIsDMABufPrefWebGLState = Preferences::GetBool(DMABUF_WEBGL_PREF, false);
-      sRenderingCacheModePref = Preferences::GetInt(CACHE_MODE_PREF, 0);
       sIsPrefLoaded = true;
     }
 
diff -up firefox-74.0/widget/gtk/nsWaylandDisplay.h.mozilla-1623060 firefox-74.0/widget/gtk/nsWaylandDisplay.h
--- firefox-74.0/widget/gtk/nsWaylandDisplay.h.mozilla-1623060	2020-03-17 14:19:04.394231493 +0100
+++ firefox-74.0/widget/gtk/nsWaylandDisplay.h	2020-03-17 14:22:49.867838072 +0100
@@ -91,9 +91,6 @@ class nsWaylandDisplay {
   static bool IsDMABufTexturesEnabled();
   static bool IsDMABufWebGLEnabled();
 
-  // See WindowSurfaceWayland::CacheMode for details.
-  int GetRenderingCacheModePref() { return sRenderingCacheModePref; };
-
  private:
   bool ConfigureGbm();
 
@@ -121,8 +118,7 @@ class nsWaylandDisplay {
   static int sIsDMABufPrefTextState;
   static int sIsDMABufPrefBasicCompositorState;
   static int sIsDMABufPrefWebGLState;
-  static bool sIsDMABufConfigured;
-  static int sRenderingCacheModePref;
+  static bool sIsDMABufConfigured;  
   static bool sIsPrefLoaded;
 };
 
diff -up firefox-74.0/widget/gtk/nsWindow.cpp.mozilla-1623060 firefox-74.0/widget/gtk/nsWindow.cpp
--- firefox-74.0/widget/gtk/nsWindow.cpp.mozilla-1623060	2020-03-17 14:19:04.393231499 +0100
+++ firefox-74.0/widget/gtk/nsWindow.cpp	2020-03-17 14:19:04.395231487 +0100
@@ -7839,3 +7839,15 @@ void nsWindow::SetEGLNativeWindowSize(
 
 nsWindow* nsWindow::GetFocusedWindow() { return gFocusWindow; }
 #endif
+
+LayoutDeviceIntRect nsWindow::GetMozContainerSize() {
+  LayoutDeviceIntRect size(0, 0, 0, 0);
+  if (mContainer) {
+    GtkAllocation allocation;
+    gtk_widget_get_allocation(GTK_WIDGET(mContainer), &allocation);
+    int scale = GdkScaleFactor();
+    size.width = allocation.width * scale;
+    size.height = allocation.height * scale;
+  }
+  return size;
+}
diff -up firefox-74.0/widget/gtk/nsWindow.h.mozilla-1623060 firefox-74.0/widget/gtk/nsWindow.h
--- firefox-74.0/widget/gtk/nsWindow.h.mozilla-1623060	2020-03-09 14:10:19.000000000 +0100
+++ firefox-74.0/widget/gtk/nsWindow.h	2020-03-17 14:19:04.395231487 +0100
@@ -291,6 +291,7 @@ class nsWindow final : public nsBaseWidg
                                                 int32_t aVertical) override;
 
   MozContainer* GetMozContainer() { return mContainer; }
+  LayoutDeviceIntRect GetMozContainerSize();
   // GetMozContainerWidget returns the MozContainer even for undestroyed
   // descendant windows
   GtkWidget* GetMozContainerWidget();
diff -up firefox-74.0/widget/gtk/WindowSurfaceWayland.cpp.mozilla-1623060 firefox-74.0/widget/gtk/WindowSurfaceWayland.cpp
--- firefox-74.0/widget/gtk/WindowSurfaceWayland.cpp.mozilla-1623060	2020-03-09 14:10:19.000000000 +0100
+++ firefox-74.0/widget/gtk/WindowSurfaceWayland.cpp	2020-03-17 14:19:04.394231493 +0100
@@ -527,9 +527,6 @@ WindowSurfaceWayland::WindowSurfaceWayla
     mShmBackupBuffer[i] = nullptr;
     mDMABackupBuffer[i] = nullptr;
   }
-  mRenderingCacheMode = static_cast<RenderingCacheMode>(
-      mWaylandDisplay->GetRenderingCacheModePref());
-  LOGWAYLAND(("WindowSurfaceWayland Cache mode %d\n", mRenderingCacheMode));
 }
 
 WindowSurfaceWayland::~WindowSurfaceWayland() {
@@ -650,14 +647,13 @@ WindowBackBuffer* WindowSurfaceWayland::
   LOGWAYLAND(
       ("WindowSurfaceWayland::NewWaylandBuffer [%p] Requested buffer [%d "
        "x %d] DMABuf %d\n",
-       (void*)this, mBufferScreenRect.width, mBufferScreenRect.height,
-       aUseDMABufBackend));
+       (void*)this, mWidgetRect.width, mWidgetRect.height, aUseDMABufBackend));
 
   mWaylandBuffer = WaylandBufferFindAvailable(
-      mBufferScreenRect.width, mBufferScreenRect.height, aUseDMABufBackend);
+      mWidgetRect.width, mWidgetRect.height, aUseDMABufBackend);
   if (!mWaylandBuffer) {
-    mWaylandBuffer = CreateWaylandBuffer(
-        mBufferScreenRect.width, mBufferScreenRect.height, aUseDMABufBackend);
+    mWaylandBuffer = CreateWaylandBuffer(mWidgetRect.width, mWidgetRect.height,
+                                         aUseDMABufBackend);
   }
 
   return mWaylandBuffer;
@@ -667,7 +663,7 @@ WindowBackBuffer* WindowSurfaceWayland::
   LOGWAYLAND(
       ("WindowSurfaceWayland::GetWaylandBufferRecent [%p] Requested buffer [%d "
        "x %d]\n",
-       (void*)this, mBufferScreenRect.width, mBufferScreenRect.height));
+       (void*)this, mWidgetRect.width, mWidgetRect.height));
 
   // There's no buffer created yet, create a new one for partial screen updates.
   if (!mWaylandBuffer) {
@@ -679,10 +675,9 @@ WindowBackBuffer* WindowSurfaceWayland::
     return nullptr;
   }
 
-  if (mWaylandBuffer->IsMatchingSize(mBufferScreenRect.width,
-                                     mBufferScreenRect.height)) {
-    LOGWAYLAND(("    Size is ok, use the buffer [%d x %d]\n",
-                mBufferScreenRect.width, mBufferScreenRect.height));
+  if (mWaylandBuffer->IsMatchingSize(mWidgetRect.width, mWidgetRect.height)) {
+    LOGWAYLAND(("    Size is ok, use the buffer [%d x %d]\n", mWidgetRect.width,
+                mWidgetRect.height));
     return mWaylandBuffer;
   }
 
@@ -697,7 +692,7 @@ WindowBackBuffer* WindowSurfaceWayland::
   LOGWAYLAND(
       ("WindowSurfaceWayland::GetWaylandBufferWithSwitch [%p] Requested buffer "
        "[%d x %d]\n",
-       (void*)this, mBufferScreenRect.width, mBufferScreenRect.height));
+       (void*)this, mWidgetRect.width, mWidgetRect.height));
 
   // There's no buffer created yet or actual buffer is attached, get a new one.
   // Use DMABuf for fullscreen updates only.
@@ -706,18 +701,21 @@ WindowBackBuffer* WindowSurfaceWayland::
   }
 
   // Reuse existing buffer
-  LOGWAYLAND(("    Reuse buffer with resize [%d x %d]\n",
-              mBufferScreenRect.width, mBufferScreenRect.height));
+  LOGWAYLAND(("    Reuse buffer with resize [%d x %d]\n", mWidgetRect.width,
+              mWidgetRect.height));
 
   // OOM here, just return null to skip this frame.
-  if (!mWaylandBuffer->Resize(mBufferScreenRect.width,
-                              mBufferScreenRect.height)) {
+  if (!mWaylandBuffer->Resize(mWidgetRect.width, mWidgetRect.height)) {
     return nullptr;
   }
   return mWaylandBuffer;
 }
 
 already_AddRefed<gfx::DrawTarget> WindowSurfaceWayland::LockWaylandBuffer() {
+  // Allocated wayland buffer must match widget size, otherwise wayland
+  // compositor is confused and may produce various rendering artifacts.
+  mWidgetRect = mWindow->GetMozContainerSize();
+
   // mCanSwitchWaylandBuffer set means we're getting buffer for fullscreen
   // update. We can use DMABuf and we can get a new buffer for drawing.
   WindowBackBuffer* buffer = mCanSwitchWaylandBuffer
@@ -858,12 +856,12 @@ already_AddRefed<gfx::DrawTarget> Window
   LOGWAYLAND(("   windowRedraw = %d\n", windowRedraw));
 
 #if MOZ_LOGGING
-  if (!(mBufferScreenRect == lockedScreenRect)) {
+  if (!(mLockedScreenRect == lockedScreenRect)) {
     LOGWAYLAND(("   screen size changed\n"));
   }
 #endif
 
-  if (!(mBufferScreenRect == lockedScreenRect)) {
+  if (!(mLockedScreenRect == lockedScreenRect)) {
     // Screen (window) size changed and we still have some painting pending
     // for the last window size. That can happen when window is resized.
     // We can't commit them any more as they're for former window size, so
@@ -878,17 +876,21 @@ already_AddRefed<gfx::DrawTarget> Window
       // as it produces artifacts.
       return nullptr;
     }
-    mBufferScreenRect = lockedScreenRect;
+    mLockedScreenRect = lockedScreenRect;
   }
 
-  if (mRenderingCacheMode == CACHE_ALL) {
-    mDrawToWaylandBufferDirectly = windowRedraw;
-  } else if (mRenderingCacheMode == CACHE_MISSING) {
+  LayoutDeviceIntRect size = mWindow->GetMozContainerSize();
+
+  // We can draw directly only when widget has the same size as wl_buffer
+  mDrawToWaylandBufferDirectly = (size.width == mLockedScreenRect.width &&
+                                  size.height == mLockedScreenRect.height);
+
+  // We can draw directly only when we redraw significant part of the window
+  // to avoid flickering.
+  if (mDrawToWaylandBufferDirectly) {
     mDrawToWaylandBufferDirectly =
         windowRedraw || (lockSize.width * 3 > lockedScreenRect.width &&
                          lockSize.height * 3 > lockedScreenRect.height);
-  } else {
-    mDrawToWaylandBufferDirectly = true;
   }
 
   if (mDrawToWaylandBufferDirectly) {
@@ -903,11 +905,6 @@ already_AddRefed<gfx::DrawTarget> Window
     }
   }
 
-  // Any caching is disabled and we don't have any back buffer available.
-  if (mRenderingCacheMode == CACHE_NONE) {
-    return nullptr;
-  }
-
   // We do indirect drawing because there isn't any front buffer available.
   // Do indirect drawing to mImageSurface which is commited to wayland
   // wl_buffer by DrawDelayedImageCommits() later.
@@ -1151,7 +1148,7 @@ void WindowSurfaceWayland::Commit(const
         ("WindowSurfaceWayland::Commit [%p] damage size [%d, %d] -> [%d x %d]"
          "screenSize [%d x %d]\n",
          (void*)this, lockSize.x, lockSize.y, lockSize.width, lockSize.height,
-         mBufferScreenRect.width, mBufferScreenRect.height));
+         mLockedScreenRect.width, mLockedScreenRect.height));
     LOGWAYLAND(("    mDrawToWaylandBufferDirectly = %d\n",
                 mDrawToWaylandBufferDirectly));
   }
diff -up firefox-74.0/widget/gtk/WindowSurfaceWayland.h.mozilla-1623060 firefox-74.0/widget/gtk/WindowSurfaceWayland.h
--- firefox-74.0/widget/gtk/WindowSurfaceWayland.h.mozilla-1623060	2020-03-09 14:10:18.000000000 +0100
+++ firefox-74.0/widget/gtk/WindowSurfaceWayland.h	2020-03-17 14:19:04.394231493 +0100
@@ -261,8 +261,14 @@ class WindowSurfaceWayland : public Wind
   nsWindow* mWindow;
   // Buffer screen rects helps us understand if we operate on
   // the same window size as we're called on WindowSurfaceWayland::Lock().
-  // mBufferScreenRect is window size when our wayland buffer was allocated.
-  LayoutDeviceIntRect mBufferScreenRect;
+  // mLockedScreenRect is window size when our wayland buffer was allocated.
+  LayoutDeviceIntRect mLockedScreenRect;
+
+  // WidgetRect is an actual size of mozcontainer widget. It can be
+  // different than mLockedScreenRect during resize when mBounds are updated
+  // immediately but actual GtkWidget size is updated asynchronously
+  // (see Bug 1489463).
+  LayoutDeviceIntRect mWidgetRect;
   nsWaylandDisplay* mWaylandDisplay;
 
   // Actual buffer (backed by wl_buffer) where all drawings go into.
@@ -327,9 +333,6 @@ class WindowSurfaceWayland : public Wind
 
   bool mIsMainThread;
 
-  // Image caching strategy, see RenderingCacheMode for details.
-  RenderingCacheMode mRenderingCacheMode;
-
   static bool UseDMABufBackend();
   static bool mUseDMABufInitialized;
   static bool mUseDMABuf;