Clear IOSurfaces immediately after creating them.

Calling IOSurfaceLock() followed by IOSurfaceUnlock() appears sufficient.

BUG=584760

Review URL: https://codereview.chromium.org/1709443002

Cr-Commit-Position: refs/heads/master@{#376054}

ui/gfx/mac/io_surface.cc

@@ -148,7 +148,16 @@ IOSurfaceRef CreateIOSurface(const gfx::Size& size, gfx::BufferFormat format) {
                     BytesPerElement(format, 0));
   }
 
-  return IOSurfaceCreate(properties);
+  IOSurfaceRef surface = IOSurfaceCreate(properties);
+
+  // Zero-initialize the IOSurface. Calling IOSurfaceLock/IOSurfaceUnlock
+  // appears to be sufficient. https://crbug.com/584760#c17
+  IOReturn r = IOSurfaceLock(surface, 0, nullptr);
+  DCHECK_EQ(kIOReturnSuccess, r);
+  r = IOSurfaceUnlock(surface, 0, nullptr);
+  DCHECK_EQ(kIOReturnSuccess, r);
+
+  return surface;
 }
 
 }  // namespace gfx

ui/gl/test/gl_image_test_template.h

@@ -177,9 +177,7 @@ class GLImageZeroInitializeTest : public GLImageTest<GLImageTestDelegate> {};
 // result is zero-initialized.
 TYPED_TEST_CASE_P(GLImageZeroInitializeTest);
 
-// TODO(erikchen): Enable this test when it actually passes on Mac.
-// https://crbug.com/584760.
-TYPED_TEST_P(GLImageZeroInitializeTest, DISABLED_ZeroInitialize) {
+TYPED_TEST_P(GLImageZeroInitializeTest, ZeroInitialize) {
   const gfx::Size image_size(256, 256);
 
   GLuint framebuffer =
@@ -217,7 +215,7 @@ TYPED_TEST_P(GLImageZeroInitializeTest, DISABLED_ZeroInitialize) {
   image->Destroy(true /* have_context */);
 }
 
-REGISTER_TYPED_TEST_CASE_P(GLImageZeroInitializeTest, DISABLED_ZeroInitialize);
+REGISTER_TYPED_TEST_CASE_P(GLImageZeroInitializeTest, ZeroInitialize);
 
 template <typename GLImageTestDelegate>
 class GLImageCopyTest : public GLImageTest<GLImageTestDelegate> {};