Force spontaneous draws into the SW path

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/command_line.h"
+#include "base/auto_reset.h"
 #include "base/logging.h"
-#include "base/time.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/compositor_frame.h"
-#include "cc/output/compositor_frame_ack.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface_client.h"
 #include "cc/output/software_output_device.h"
 #include "content/browser/android/in_process/synchronous_compositor_impl.h"
 #include "content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h"
-#include "content/public/browser/android/synchronous_compositor_client.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/common/content_switches.h"
-#include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
-#include "third_party/skia/include/core/SkPicture.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/gfx/transform.h"
 #include "ui/gl/gl_context.h"
 #include "webkit/common/gpu/webgraphicscontext3d_in_process_command_buffer_impl.h"
 
 using webkit::gpu::WebGraphicsContext3DInProcessCommandBufferImpl;
 
 namespace content {
 
@@ skipping 46 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(SoftwareDevice);
 };
 
 SynchronousCompositorOutputSurface::SynchronousCompositorOutputSurface(
     int routing_id)
     : cc::OutputSurface(
           scoped_ptr<cc::SoftwareOutputDevice>(new SoftwareDevice(this))),
       routing_id_(routing_id),
       needs_begin_frame_(false),
+      invoking_composite_(false),
       did_swap_buffer_(false),
       current_sw_canvas_(NULL) {
   capabilities_.deferred_gl_initialization = true;
   capabilities_.adjust_deadline_for_parent = false;
   // Cannot call out to GetDelegate() here as the output surface is not
   // constructed on the correct thread.
 }
 
 SynchronousCompositorOutputSurface::~SynchronousCompositorOutputSurface() {
   DCHECK(CalledOnValidThread());
   SynchronousCompositorOutputSurfaceDelegate* delegate = GetDelegate();
   if (delegate)
     delegate->DidDestroySynchronousOutputSurface(this);
 }
 
 bool SynchronousCompositorOutputSurface::ForcedDrawToSoftwareDevice() const {
-  return current_sw_canvas_ != NULL;
+  // |current_sw_canvas_| indicates we're in a DemandDrawSw call. In addition
+  // |invoking_composite_| == false indicates an attempt to draw outside of
+  // the synchronous compositor's control: force it into SW path and hence to
+  // the null canvas (and will log a warning there).
+  return current_sw_canvas_ != NULL || !invoking_composite_;
 }
 
 bool SynchronousCompositorOutputSurface::BindToClient(
     cc::OutputSurfaceClient* surface_client) {
   DCHECK(CalledOnValidThread());
   if (!cc::OutputSurface::BindToClient(surface_client))
     return false;
   SynchronousCompositorOutputSurfaceDelegate* delegate = GetDelegate();
   if (delegate)
     delegate->DidBindOutputSurface(this);
@@ skipping 71 matching lines @@
 
   // TODO(boliu): Check if context is lost here.
 
   return did_swap_buffer_;
 }
 
 bool SynchronousCompositorOutputSurface::DemandDrawSw(SkCanvas* canvas) {
   DCHECK(CalledOnValidThread());
   DCHECK(canvas);
   DCHECK(!current_sw_canvas_);
-  current_sw_canvas_ = canvas;
+  base::AutoReset<SkCanvas*> canvas_resetter(&current_sw_canvas_, canvas);
 
   SkIRect canvas_clip;
   canvas->getClipDeviceBounds(&canvas_clip);
   gfx::Rect clip = gfx::SkIRectToRect(canvas_clip);
 
   gfx::Transform transform(gfx::Transform::kSkipInitialization);
   transform.matrix() = canvas->getTotalMatrix();  // Converts 3x3 matrix to 4x4.
   AdjustTransformForClip(&transform, clip);
 
   surface_size_ = gfx::Size(canvas->getDeviceSize().width(),
                             canvas->getDeviceSize().height());
   SetExternalDrawConstraints(transform, clip);
 
   InvokeComposite(clip.size());
 
-  current_sw_canvas_ = NULL;
   return did_swap_buffer_;
 }
 
 void SynchronousCompositorOutputSurface::InvokeComposite(
     gfx::Size damage_size) {
+  DCHECK(!invoking_composite_);
+  base::AutoReset<bool> invoking_composite_resetter(&invoking_composite_, true);
   did_swap_buffer_ = false;
   SetNeedsRedrawRect(gfx::Rect(damage_size));
   if (needs_begin_frame_)
     BeginFrame(cc::BeginFrameArgs::CreateForSynchronousCompositor());
 
   if (did_swap_buffer_)
     OnSwapBuffersComplete(NULL);
 }
 
 void SynchronousCompositorOutputSurface::PostCheckForRetroactiveBeginFrame() {
   // Synchronous compositor cannot perform retroactive begin frames, so
   // intentionally no-op here.
 }
 
 // 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);
 }
 
 SynchronousCompositorOutputSurfaceDelegate*
 SynchronousCompositorOutputSurface::GetDelegate() {
   return SynchronousCompositorImpl::FromRoutingID(routing_id_);
 }
 
 }  // namespace content