android webview: allow cc to fail hardware draw

content/browser/android/in_process/synchronous_compositor_output_surface.cc

 // Copyright 2013 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/in_process/synchronous_compositor_output_surface.h"
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/context_provider.h"
@@ skipping 56 matching lines @@
     scoped_refptr<FrameSwapMessageQueue> frame_swap_message_queue)
     : cc::OutputSurface(
           context_provider,
           worker_context_provider,
           scoped_ptr<cc::SoftwareOutputDevice>(new SoftwareDevice(this))),
       routing_id_(routing_id),
       registered_(false),
       current_sw_canvas_(nullptr),
       memory_policy_(0),
       frame_swap_message_queue_(frame_swap_message_queue) {
-  capabilities_.draw_and_swap_full_viewport_every_frame = true;
   capabilities_.adjust_deadline_for_parent = false;
   capabilities_.delegated_rendering = true;
   capabilities_.max_frames_pending = 1;
   memory_policy_.priority_cutoff_when_visible =
       gpu::MemoryAllocation::CUTOFF_ALLOW_NICE_TO_HAVE;
 }
 
 SynchronousCompositorOutputSurface::~SynchronousCompositorOutputSurface() {
 }
 
@@ skipping 118 matching lines @@
   DCHECK(!frame_holder_.get());
 
   gfx::Transform adjusted_transform = transform;
   AdjustTransform(&adjusted_transform, viewport);
   SetExternalDrawConstraints(adjusted_transform,
                              viewport,
                              clip,
                              viewport_rect_for_tile_priority,
                              transform_for_tile_priority,
                              !hardware_draw);
-  SetNeedsRedrawRect(gfx::Rect(viewport.size()));
+  if (!hardware_draw) {
+    SetNeedsRedrawRect(gfx::Rect(viewport.size()));
+  }
 
   client_->OnDraw();
 
   // After software draws (which might move the viewport arbitrarily), restore
   // the previous hardware viewport to allow CC's tile manager to prioritize
   // properly.
   if (hardware_draw) {
     cached_hw_transform_ = adjusted_transform;
     cached_hw_viewport_ = viewport;
     cached_hw_clip_ = clip;
@@ skipping 56 matching lines @@
 }
 
 // Not using base::NonThreadSafe as we want to enforce a more exacting threading
 // requirement: SynchronousCompositorOutputSurface() must only be used on the UI
 // thread.
 bool SynchronousCompositorOutputSurface::CalledOnValidThread() const {
   return BrowserThread::CurrentlyOn(BrowserThread::UI);
 }
 
 }  // namespace content