cc: Fix resource provider fences and add DCHECKs.

When I added the resource provider fence concept, I didn't
extend the read-fence long enough (it currently only protects
the current frame). This extends the read-lock for one frame.

BUG=172995

Review URL: https://chromiumcodereview.appspot.com/12220095

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182162 0039d316-1c4b-4281-b951-d872f2087c98

cc/gl_renderer.cc

@@ -1324,11 +1324,6 @@ bool GLRenderer::swapBuffers()
     TRACE_EVENT0("cc", "GLRenderer::swapBuffers");
     // We're done! Time to swapbuffers!
 
-    scoped_refptr<ResourceProvider::Fence> lastSwapFence = m_resourceProvider->getReadLockFence();
-    if (lastSwapFence)
-        static_cast<SimpleSwapFence*>(lastSwapFence.get())->setHasPassed();
-    m_resourceProvider->setReadLockFence(new SimpleSwapFence());
-
     if (m_capabilities.usingPartialSwap) {
         // If supported, we can save significant bandwidth by only swapping the damaged/scissored region (clamped to the viewport)
         m_swapBufferRect.Intersect(gfx::Rect(gfx::Point(), viewportSize()));
@@ -1342,6 +1337,14 @@ bool GLRenderer::swapBuffers()
 
     m_swapBufferRect = gfx::Rect();
 
+    // We don't have real fences, so we mark read fences as passed
+    // assuming a double-buffered GPU pipeline. A texture can be
+    // written to after one full frame has past since it was last read.
+    if (m_lastSwapFence)
+        static_cast<SimpleSwapFence*>(m_lastSwapFence.get())->setHasPassed();
+    m_lastSwapFence = m_resourceProvider->getReadLockFence();
+    m_resourceProvider->setReadLockFence(new SimpleSwapFence());
+
     return true;
 }
 

cc/gl_renderer.h

@@ -231,6 +231,8 @@ private:
 
     scoped_ptr<ResourceProvider::ScopedWriteLockGL> m_currentFramebufferLock;
 
+    scoped_refptr<ResourceProvider::Fence> m_lastSwapFence;
+
     DISALLOW_COPY_AND_ASSIGN(GLRenderer);
 };
 

content/renderer/gpu/compositor_output_surface.cc

@@ -149,10 +149,10 @@ namespace {
 
 void CompositorOutputSurface::UpdateSmoothnessTakesPriority(
     bool prefers_smoothness) {
-#if ENABLE_DCHECK
+#ifndef NDEBUG
   // If we use different compositor threads, we need to
   // use an atomic int to track prefer smoothness count.
-  static int g_last_thread = base::PlatformThread::CurrentId();
+  base::PlatformThreadId g_last_thread = base::PlatformThread::CurrentId();
   DCHECK_EQ(g_last_thread, base::PlatformThread::CurrentId());
 #endif
   if (prefers_smoothness_ == prefers_smoothness)