gpu: Add async pixel transfer interface, stub and tests.

gpu/command_buffer/service/texture_manager.h

Index: gpu/command_buffer/service/texture_manager.h
diff --git a/gpu/command_buffer/service/texture_manager.h b/gpu/command_buffer/service/texture_manager.h
index f2e7963e7cf3e4204c66aa4037adbc5c7d0ac9f9..fca514ca357fe72b795119bcdc2951df8f1b69fa 100644
--- a/gpu/command_buffer/service/texture_manager.h
+++ b/gpu/command_buffer/service/texture_manager.h
@@ -14,6 +14,7 @@
 #include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/gpu_export.h"
+#include "ui/gl/async_pixel_transfer_delegate.h"
 #include "ui/gl/gl_image.h"
 
 namespace gpu {
@@ -175,6 +176,23 @@ class GPU_EXPORT TextureManager {
       return stream_texture_;
     }
 
+    gfx::AsyncPixelTransferState* GetAsyncTransferState() const {
+      return async_transfer_state_.get();
+    }
+    void SetAsyncTransferState(gfx::AsyncPixelTransferState* state) {
+      async_transfer_state_ = state;
+    }
+    bool AsyncTransferIsInProgress() {
+      return async_transfer_state_

[greggman, 2012/12/12 03:51:36]

style: operators want to be at the end of the line

[epennerAtGoogle, 2012/12/12 04:49:49]

Done.

+          && async_transfer_state_->TransferIsInProgress();
+    }
+    bool BindAsyncTransferToTexture(GLenum target) {
+      DCHECK(async_transfer_state_);

[greggman, 2012/12/12 03:51:36]

It seems like this DCHECK is in conflict with the if below. Should this function
have the if, in which case it shouldn't have the DCHECK? Or should it not have
the if and should have the DCHECK?

[epennerAtGoogle, 2012/12/12 04:49:49]

Done.

+      if (async_transfer_state_)
+        return async_transfer_state_->BindAsyncTransferToTexture(target);
+      return false;
+    }
+
     void SetImmutable(bool immutable) {
       immutable_ = immutable;
     }
@@ -337,6 +355,9 @@ class GPU_EXPORT TextureManager {
     // Whether this is a special streaming texture.
     bool stream_texture_;
 
+    // State to facilitate async transfers on this texture.
+    scoped_refptr<gfx::AsyncPixelTransferState> async_transfer_state_;
+
     // Whether the texture is immutable and no further changes to the format
     // or dimensions of the texture object can be made.
     bool immutable_;