Mac: Fix black flashing during tab switch

content/browser/compositor/gpu_browser_compositor_output_surface.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/compositor/gpu_browser_compositor_output_surface.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/output/output_surface_client.h"
 #include "content/browser/compositor/browser_compositor_overlay_candidate_validator.h"
 #include "content/browser/compositor/reflector_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/common/gpu/client/context_provider_command_buffer.h"
 #include "content/public/browser/browser_thread.h"
 #include "gpu/command_buffer/client/context_support.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 
 namespace content {
 
 GpuBrowserCompositorOutputSurface::GpuBrowserCompositorOutputSurface(
     const scoped_refptr<ContextProviderCommandBuffer>& context,
     const scoped_refptr<ui::CompositorVSyncManager>& vsync_manager,
     scoped_ptr<BrowserCompositorOverlayCandidateValidator>
         overlay_candidate_validator)
     : BrowserCompositorOutputSurface(context,
                                      vsync_manager,
                                      overlay_candidate_validator.Pass()),
 #if defined(OS_MACOSX)
-      should_not_show_frames_(false),
+      should_show_frames_state_(SHOULD_SHOW_FRAMES),
 #endif
       swap_buffers_completion_callback_(
           base::Bind(&GpuBrowserCompositorOutputSurface::OnSwapBuffersCompleted,
                      base::Unretained(this))),
       update_vsync_parameters_callback_(base::Bind(
           &BrowserCompositorOutputSurface::OnUpdateVSyncParametersFromGpu,
           base::Unretained(this))) {
 }
 
 GpuBrowserCompositorOutputSurface::~GpuBrowserCompositorOutputSurface() {}
@@ skipping 39 matching lines @@
       gfx::Rect(frame->gl_frame_data->size)) {
     context_provider_->ContextSupport()->Swap();
   } else {
     context_provider_->ContextSupport()->PartialSwapBuffers(
         frame->gl_frame_data->sub_buffer_rect);
   }
 
   client_->DidSwapBuffers();
 
 #if defined(OS_MACOSX)
-  if (should_not_show_frames_)
-    should_not_show_frames_ = false;
+  if (should_show_frames_state_ ==
+      SHOULD_NOT_SHOW_FRAMES_NO_SWAP_AFTER_SUSPENDED) {
+    should_show_frames_state_ = SHOULD_SHOW_FRAMES;
+  }
 #endif
 }
 
 void GpuBrowserCompositorOutputSurface::OnSwapBuffersCompleted(
     const std::vector<ui::LatencyInfo>& latency_info) {
 #if defined(OS_MACOSX)
   // On Mac, delay acknowledging the swap to the output surface client until
   // it has been drawn, see OnSurfaceDisplayed();
   NOTREACHED();
 #else
   if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
     RenderWidgetHostImpl::CompositorFrameDrawn(latency_info);
   } else {
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
         base::Bind(&RenderWidgetHostImpl::CompositorFrameDrawn, latency_info));
   }
   OnSwapBuffersComplete();
 #endif
 }
 
 #if defined(OS_MACOSX)
 void GpuBrowserCompositorOutputSurface::OnSurfaceDisplayed() {
   cc::OutputSurface::OnSwapBuffersComplete();
 }
 
-void GpuBrowserCompositorOutputSurface::OnSurfaceRecycled() {
-  // Discard the backbuffer immediately. This is necessary only when using a
-  // ImageTransportSurfaceFBO with a CALayerStorageProvider. Discarding the
-  // backbuffer results in the next frame using a new CALayer and CAContext,
-  // which guarantees that the browser will not flash stale content when adding
-  // the remote CALayer to the NSView hierarchy (it could flash stale content
-  // because the system window server is not synchronized with any signals we
-  // control or observe).
-  DiscardBackbuffer();
-  // It may be that there are frames in-flight from the GPU process back to the
-  // browser. Make sure that these frames are not displayed by ignoring them in
-  // GpuProcessHostUIShim, until the browser issues a SwapBuffers for the new
-  // content.
-  should_not_show_frames_ = true;
+void GpuBrowserCompositorOutputSurface::SetSurfaceSuspendedForRecycle(
+    bool suspended) {
+  if (suspended) {
+    // It may be that there are frames in-flight from the GPU process back to
+    // the browser. Make sure that these frames are not displayed by ignoring
+    // them in GpuProcessHostUIShim, until the browser issues a SwapBuffers for
+    // the new content.
+    should_show_frames_state_ = SHOULD_NOT_SHOW_FRAMES_SUSPENDED;
+  } else {
+    // Discard the backbuffer before drawing the new frame. This is necessary
+    // only when using a ImageTransportSurfaceFBO with a
+    // CALayerStorageProvider. Discarding the backbuffer results in the next
+    // frame using a new CALayer and CAContext, which guarantees that the
+    // browser will not flash stale content when adding the remote CALayer to
+    // the NSView hierarchy (it could flash stale content because the system
+    // window server is not synchronized with any signals we control or
+    // observe).
+    if (should_show_frames_state_ == SHOULD_NOT_SHOW_FRAMES_SUSPENDED) {
+      DiscardBackbuffer();
+      should_show_frames_state_ =
+          SHOULD_NOT_SHOW_FRAMES_NO_SWAP_AFTER_SUSPENDED;
+    }
+  }
 }
 
-bool GpuBrowserCompositorOutputSurface::ShouldNotShowFramesAfterRecycle()
-    const {
-  return should_not_show_frames_;
+bool GpuBrowserCompositorOutputSurface::
+    SurfaceShouldNotShowFramesAfterSuspendForRecycle() const {
+  return should_show_frames_state_ != SHOULD_SHOW_FRAMES;
 }
 #endif
 
 }  // namespace content