Reject CompositorFrames with no render passes when deserializing

content/browser/android/synchronous_compositor_host.cc

 // Copyright 2015 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/android/synchronous_compositor_host.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/containers/hash_tables.h"
@@ skipping 158 matching lines @@
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedSetSkCanvas);
 };
 
 }
 
 bool SynchronousCompositorHost::DemandDrawSwInProc(SkCanvas* canvas) {
   SyncCompositorCommonRendererParams common_renderer_params;
-  bool success = false;
-  std::unique_ptr<cc::CompositorFrame> frame(new cc::CompositorFrame);
+  base::Optional<cc::CompositorFrameMetadata> metadata;
   ScopedSetSkCanvas set_sk_canvas(canvas);
   SyncCompositorDemandDrawSwParams params;  // Unused.
   {
     base::ThreadRestrictions::ScopedAllowWait wait;
     if (!sender_->Send(new SyncCompositorMsg_DemandDrawSw(
-            routing_id_, params, &success, &common_renderer_params,
-            frame.get()))) {
+            routing_id_, params, &common_renderer_params, &metadata))) {
       return false;
     }
   }
-  if (!success)
+  if (!metadata)
     return false;
   ProcessCommonParams(common_renderer_params);
-  UpdateFrameMetaData(std::move(frame->metadata));
+  UpdateFrameMetaData(std::move(*metadata));
   return true;
 }
 
 class SynchronousCompositorHost::ScopedSendZeroMemory {
  public:
   ScopedSendZeroMemory(SynchronousCompositorHost* host) : host_(host) {}
   ~ScopedSendZeroMemory() { host_->SendZeroMemory(); }
 
  private:
   SynchronousCompositorHost* const host_;
@@ skipping 31 matching lines @@
   DCHECK_EQ(kRGBA_8888_SkColorType, info.colorType());
   size_t stride = info.minRowBytes();
   size_t buffer_size = info.getSafeSize(stride);
   if (!buffer_size)
     return false;  // Overflow.
 
   SetSoftwareDrawSharedMemoryIfNeeded(stride, buffer_size);
   if (!software_draw_shm_)
     return false;
 
-  std::unique_ptr<cc::CompositorFrame> frame(new cc::CompositorFrame);
+  base::Optional<cc::CompositorFrameMetadata> metadata;
   SyncCompositorCommonRendererParams common_renderer_params;
-  bool success = false;
   {
     base::ThreadRestrictions::ScopedAllowWait wait;
     if (!sender_->Send(new SyncCompositorMsg_DemandDrawSw(
-            routing_id_, params, &success, &common_renderer_params,
-            frame.get()))) {
+            routing_id_, params, &common_renderer_params, &metadata))) {
       return false;
     }
   }
   ScopedSendZeroMemory send_zero_memory(this);
-  if (!success)
+  if (!metadata)
     return false;
 
   ProcessCommonParams(common_renderer_params);
-  UpdateFrameMetaData(std::move(frame->metadata));
+  UpdateFrameMetaData(std::move(*metadata));
 
   SkBitmap bitmap;
   if (!bitmap.installPixels(info, software_draw_shm_->shm.memory(), stride))
     return false;
 
   {
     TRACE_EVENT0("browser", "DrawBitmap");
     canvas->save();
     canvas->resetMatrix();
     canvas->drawBitmap(bitmap, 0, 0);
@@ skipping 147 matching lines @@
   if (params.page_scale_factor) {
     client_->UpdateRootLayerState(
         this, gfx::ScrollOffsetToVector2dF(params.total_scroll_offset),
         gfx::ScrollOffsetToVector2dF(params.max_scroll_offset),
         params.scrollable_size, params.page_scale_factor,
         params.min_page_scale_factor, params.max_page_scale_factor);
   }
 }
 
 }  // namespace content