Revert "Revert 210138 "Perform glReadPixels with PBOs in the gpu, if PBO...""

gpu/command_buffer/tests/gl_readback_unittests.cc

Index: gpu/command_buffer/tests/gl_readback_unittests.cc
diff --git a/gpu/command_buffer/tests/gl_readback_unittests.cc b/gpu/command_buffer/tests/gl_readback_unittests.cc
index e725213473de64de51feb280ad6da1c1deb73f04..4ebb09a6f161ba024bd0fc2e4de264bef3d60a84 100644
--- a/gpu/command_buffer/tests/gl_readback_unittests.cc
+++ b/gpu/command_buffer/tests/gl_readback_unittests.cc
@@ -6,6 +6,9 @@
 #include <GLES2/gl2ext.h>
 #include <GLES2/gl2extchromium.h>
 
+#include "base/bind.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "gpu/command_buffer/tests/gl_manager.h"
 #include "gpu/command_buffer/tests/gl_test_utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -23,38 +26,28 @@ class GLReadbackTest : public testing::Test {
     gl_.Destroy();
   }
 
-  GLManager gl_;
-};
+  static void WaitForQueryCallback(int q, base::Closure cb) {
+    unsigned int done = 0;
+    glGetQueryObjectuivEXT(q, GL_QUERY_RESULT_AVAILABLE_EXT, &done);
+    if (done) {
+      cb.Run();
+    } else {
+      base::MessageLoop::current()->PostDelayedTask(
+          FROM_HERE,
+          base::Bind(&WaitForQueryCallback, q, cb),
+          base::TimeDelta::FromMilliseconds(3));
+    }
+  }
 
+  void WaitForQuery(int q) {
+    base::RunLoop run_loop;
+    WaitForQueryCallback(q, run_loop.QuitClosure());
+    run_loop.Run();
+  }
 
-TEST_F(GLReadbackTest, ReadPixelsWithPBO) {
-  const GLint kBytesPerPixel = 4;
-  const GLint kWidth = 2;
-  const GLint kHeight = 2;
+  GLManager gl_;
+};
 
-  GLuint b;
-  glClearColor(0.0, 0.0, 1.0, 1.0);
-  glClear(GL_COLOR_BUFFER_BIT);
-  glGenBuffers(1, &b);
-  glBindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, b);
-  glBufferData(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
-               kWidth * kHeight * kBytesPerPixel,
-               NULL,
-               GL_STREAM_READ);
-  glReadPixels(0, 0, kWidth, kHeight, GL_RGBA, GL_UNSIGNED_BYTE, 0);
-  unsigned char *data = static_cast<unsigned char *>(
-      glMapBufferCHROMIUM(
-          GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
-          GL_READ_ONLY));
-  EXPECT_TRUE(data);
-  EXPECT_EQ(data[0], 0);   // red
-  EXPECT_EQ(data[1], 0);   // green
-  EXPECT_EQ(data[2], 255); // blue
-  glUnmapBufferCHROMIUM(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM);
-  glBindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, 0);
-  glDeleteBuffers(1, &b);
-  GLTestHelper::CheckGLError("no errors", __LINE__);
-}
 
 TEST_F(GLReadbackTest, ReadPixelsWithPBOAndQuery) {
   const GLint kBytesPerPixel = 4;
@@ -71,14 +64,11 @@ TEST_F(GLReadbackTest, ReadPixelsWithPBOAndQuery) {
                kWidth * kHeight * kBytesPerPixel,
                NULL,
                GL_STREAM_READ);
-  glBeginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, q);
+  glBeginQueryEXT(GL_ASYNC_READ_PIXELS_COMPLETED_CHROMIUM, q);
   glReadPixels(0, 0, kWidth, kHeight, GL_RGBA, GL_UNSIGNED_BYTE, 0);
-  glEndQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
+  glEndQueryEXT(GL_ASYNC_READ_PIXELS_COMPLETED_CHROMIUM);
   glFlush();
-  unsigned int done = 0;
-  while (!done) {
-    glGetQueryObjectuivEXT(q, GL_QUERY_RESULT_AVAILABLE_EXT, &done);
-  }
+  WaitForQuery(q);
 
   // TODO(hubbe): Check that glMapBufferCHROMIUM does not block here.
   unsigned char *data = static_cast<unsigned char *>(