Revert 93066 - Execute all GL commands up to the put offset reported by a each flush.This means g...

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
===================================================================
--- gpu/command_buffer/service/gles2_cmd_decoder.cc	(revision 93137)
+++ gpu/command_buffer/service/gles2_cmd_decoder.cc	(working copy)
@@ -479,6 +479,7 @@
 
   virtual void SetResizeCallback(Callback1<gfx::Size>::Type* callback);
   virtual void SetSwapBuffersCallback(Callback0::Type* callback);
+  virtual void SetLatchCallback(const base::Callback<void(bool)>& callback);;
   virtual bool GetServiceTextureId(uint32 client_texture_id,
                                    uint32* service_texture_id);
 
@@ -1271,6 +1272,7 @@
 
   scoped_ptr<Callback1<gfx::Size>::Type> resize_callback_;
   scoped_ptr<Callback0::Type> swap_buffers_callback_;
+  base::Callback<void(bool)> latch_callback_;
 
   // The format of the back buffer_
   GLenum back_buffer_color_format_;
@@ -2358,6 +2360,11 @@
   swap_buffers_callback_.reset(callback);
 }
 
+void GLES2DecoderImpl::SetLatchCallback(
+    const base::Callback<void(bool)>& callback) {
+  latch_callback_ = callback;
+}
+
 bool GLES2DecoderImpl::GetServiceTextureId(uint32 client_texture_id,
                                            uint32* service_texture_id) {
   TextureManager::TextureInfo* texture =
@@ -6529,6 +6536,62 @@
   return error::kNoError;
 }
 
+error::Error GLES2DecoderImpl::HandleSetLatchCHROMIUM(
+    uint32 immediate_data_size, const gles2::SetLatchCHROMIUM& c) {
+  TRACE_EVENT1("gpu", "SetLatch", "latch_id", c.latch_id);
+  // Ensure the side effects of previous commands are visible to other contexts.
+  // There is no need to do this for ANGLE because it uses a
+  // single D3D device for all contexts.
+  if (!IsAngle())
+    glFlush();
+
+  int32 shm_id = gpu::kLatchSharedMemoryId;
+  uint32 latch_id = c.latch_id;
+  uint32 shm_offset = 0;
+  base::subtle::Atomic32* latch;
+  if (!SafeMultiplyUint32(latch_id, sizeof(*latch), &shm_offset)) {
+    return error::kOutOfBounds;
+  }
+  latch = GetSharedMemoryAs<base::subtle::Atomic32*>(
+      shm_id, shm_offset, sizeof(*latch));
+  if (!latch) {
+    return error::kOutOfBounds;
+  }
+  base::subtle::Atomic32 old =
+      base::subtle::NoBarrier_CompareAndSwap(latch, 0, 1);
+  DCHECK(old == 0);
+  if (!latch_callback_.is_null())
+    latch_callback_.Run(true);
+  return error::kNoError;
+}
+
+error::Error GLES2DecoderImpl::HandleWaitLatchCHROMIUM(
+    uint32 immediate_data_size, const gles2::WaitLatchCHROMIUM& c) {
+  TRACE_EVENT1("gpu", "WaitLatch", "latch_id", c.latch_id);
+  int32 shm_id = gpu::kLatchSharedMemoryId;
+  uint32 latch_id = c.latch_id;
+  uint32 shm_offset = 0;
+  base::subtle::Atomic32* latch;
+  if (!SafeMultiplyUint32(latch_id, sizeof(*latch), &shm_offset)) {
+    return error::kOutOfBounds;
+  }
+  latch = GetSharedMemoryAs<base::subtle::Atomic32*>(
+      shm_id, shm_offset, sizeof(*latch));
+  if (!latch) {
+    return error::kOutOfBounds;
+  }
+
+  base::subtle::Atomic32 old =
+      base::subtle::NoBarrier_CompareAndSwap(latch, 1, 0);
+  if (old == 0) {
+    if (!latch_callback_.is_null())
+      latch_callback_.Run(false);
+    return error::kWaiting;
+  } else {
+    return error::kNoError;
+  }
+}
+
 error::Error GLES2DecoderImpl::HandleCommandBufferEnableCHROMIUM(
     uint32 immediate_data_size, const gles2::CommandBufferEnableCHROMIUM& c) {
   Bucket* bucket = GetBucket(c.bucket_id);