gpu: Mailbox emulation with EGLImage

ui/gl/gl_fence.cc

Index: ui/gl/gl_fence.cc
diff --git a/ui/gl/gl_fence.cc b/ui/gl/gl_fence.cc
index 9b85300fabdbc10e7ecf27685930a7b55f1a2408..d8482a7e2b00c3196608020205c392d226a4adb0 100644
--- a/ui/gl/gl_fence.cc
+++ b/ui/gl/gl_fence.cc
@@ -36,6 +36,10 @@ class GLFenceNVFence: public gfx::GLFence {
     glFinishFenceNV(fence_);
   }
 
+  virtual void ServerWait() OVERRIDE {
+    glFinishFenceNV(fence_);
+  }
+
  private:
   virtual ~GLFenceNVFence() {
     glDeleteFencesNV(1, &fence_);
@@ -66,6 +70,10 @@ class GLFenceARBSync: public gfx::GLFence {
     glClientWaitSync(sync_, GL_SYNC_FLUSH_COMMANDS_BIT, GL_TIMEOUT_IGNORED);
   }
 
+  virtual void ServerWait() OVERRIDE {
+    glWaitSync(sync_, 0, GL_TIMEOUT_IGNORED);
+  }
+
  private:
   virtual ~GLFenceARBSync() {
     glDeleteSync(sync_);
@@ -96,6 +104,12 @@ class EGLFenceSync : public gfx::GLFence {
     eglClientWaitSyncKHR(display_, sync_, flags, time);
   }
 
+  virtual void ServerWait() OVERRIDE {
+    EGLint flags = 0;
+    eglWaitSyncKHR(display_, sync_, flags);
+  }
+
+
  private:
   virtual ~EGLFenceSync() {
     eglDestroySyncKHR(display_, sync_);