Don't tell browser to swap until swap actually executed.

By deferring to fence, we're ensuring that the GL commands are executed GPU side before sending a message to the browser to act on them. This is lighter weight than a glFinish because the other commands buffers on the channel (e.g. WebGL) can continue executing while we're waiting for the fence.

TEST=by hand building use_aura running http://webglsamples.googlecode.com/hg/aquarium/aquarium.html

Review URL: http://codereview.chromium.org/8497015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114798 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 29 insertions, 35 deletions

diff --git a/gpu/command_buffer/common/gl_mock.h b/gpu/command_buffer/common/gl_mock.h
index ae2259d..8ebb4c3 100644
--- a/gpu/command_buffer/common/gl_mock.h
+++ b/gpu/command_buffer/common/gl_mock.h
@@ -472,6 +472,14 @@ class MockGLInterface : public GLInterface {
 
   MOCK_METHOD3(GetFenceivNV, void(GLuint fence, GLenum pname, GLint *params));
 
+  MOCK_METHOD2(FenceSync, GLsync(GLenum condition, GLbitfield flags));
+
+  MOCK_METHOD1(DeleteSync, void(GLsync sync));
+
+  MOCK_METHOD5(GetSynciv, void(
+      GLsync sync, GLenum pname, GLsizei bufSize,
+      GLsizei* length, GLint* values));
+
   MOCK_METHOD1(SetSurfaceCHROMIUM, void(GLuint));
 
   MOCK_METHOD0(GetGraphicsResetStatusARB, GLenum());
diff --git a/gpu/command_buffer/service/gpu_scheduler.cc b/gpu/command_buffer/service/gpu_scheduler.cc
index e294dcf..cff93f2 100644
--- a/gpu/command_buffer/service/gpu_scheduler.cc
+++ b/gpu/command_buffer/service/gpu_scheduler.cc
@@ -11,6 +11,7 @@
 #include "base/message_loop.h"
 #include "base/time.h"
 #include "ui/gfx/gl/gl_bindings.h"
+#include "ui/gfx/gl/gl_fence.h"
 #include "ui/gfx/gl/gl_switches.h"
 
 using ::base::SharedMemory;
@@ -154,48 +155,28 @@ void GpuScheduler::SetCommandProcessedCallback(
 }
 
 void GpuScheduler::DeferToFence(base::Closure task) {
-  UnscheduleFence fence;
-
-  // What if either of these GL calls fails? TestFenceNV will return true and
-  // PutChanged will treat the fence as having been crossed and thereby not
-  // poll indefinately. See spec:
-  // http://www.opengl.org/registry/specs/NV/fence.txt
-  //
-  // What should happen if TestFenceNV is called for a name before SetFenceNV
-  // is called?
-  //     We generate an INVALID_OPERATION error, and return TRUE.
-  //     This follows the semantics for texture object names before
-  //     they are bound, in that they acquire their state upon binding.
-  //     We will arbitrarily return TRUE for consistency.
-  if (gfx::g_GL_NV_fence) {
-    glGenFencesNV(1, &fence.fence);
-    glSetFenceNV(fence.fence, GL_ALL_COMPLETED_NV);
-  }
-
-  glFlush();
-
-  fence.task = task;
-
-  unschedule_fences_.push(fence);
+  unschedule_fences_.push(make_linked_ptr(
+       new UnscheduleFence(gfx::GLFence::Create(), task)));
 }
 
 bool GpuScheduler::PollUnscheduleFences() {
-  if (gfx::g_GL_NV_fence) {
+  if (unschedule_fences_.empty())
+    return true;
+
+  if (unschedule_fences_.front()->fence.get()) {
     while (!unschedule_fences_.empty()) {
-      if (glTestFenceNV(unschedule_fences_.front().fence)) {
-        glDeleteFencesNV(1, &unschedule_fences_.front().fence);
-        unschedule_fences_.front().task.Run();
+      if (unschedule_fences_.front()->fence->HasCompleted()) {
+        unschedule_fences_.front()->task.Run();
         unschedule_fences_.pop();
       } else {
         return false;
       }
     }
   } else {
-    if (!unschedule_fences_.empty())
-      glFinish();
+    glFinish();
 
     while (!unschedule_fences_.empty()) {
-      unschedule_fences_.front().task.Run();
+      unschedule_fences_.front()->task.Run();
       unschedule_fences_.pop();
     }
   }
@@ -203,7 +184,8 @@ bool GpuScheduler::PollUnscheduleFences() {
   return true;
 }
 
-GpuScheduler::UnscheduleFence::UnscheduleFence() : fence(0) {
+GpuScheduler::UnscheduleFence::UnscheduleFence(
+    gfx::GLFence* fence_, base::Closure task_): fence(fence_), task(task_) {
 }
 
 GpuScheduler::UnscheduleFence::~UnscheduleFence() {
diff --git a/gpu/command_buffer/service/gpu_scheduler.h b/gpu/command_buffer/service/gpu_scheduler.h
index 3a33da4..46afc60 100644
--- a/gpu/command_buffer/service/gpu_scheduler.h
+++ b/gpu/command_buffer/service/gpu_scheduler.h
@@ -8,8 +8,8 @@
 #include <queue>
 
 #include "base/callback.h"
-#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/linked_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/shared_memory.h"
 #include "gpu/command_buffer/common/command_buffer.h"
@@ -17,6 +17,10 @@
 #include "gpu/command_buffer/service/cmd_parser.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
+namespace gfx {
+class GLFence;
+}
+
 namespace gpu {
 
 // This class schedules commands that have been flushed. They are received via
@@ -95,13 +99,13 @@ class GpuScheduler
   // The GpuScheduler will unschedule itself in the event that further GL calls
   // are issued to it before all these fences have been crossed by the GPU.
   struct UnscheduleFence {
-    UnscheduleFence();
+    UnscheduleFence(gfx::GLFence* fence, base::Closure task);
     ~UnscheduleFence();
 
-    uint32 fence;
+    scoped_ptr<gfx::GLFence> fence;
     base::Closure task;
   };
-  std::queue<UnscheduleFence> unschedule_fences_;
+  std::queue<linked_ptr<UnscheduleFence> > unschedule_fences_;
 
   base::Closure scheduled_callback_;
   base::Closure command_processed_callback_;