[GLImage] Restrict GLImageMemory creation

GLImageMemory is now created in production only from the relevant
SharedImage backing. This CL hardcodes this restriction to ensure that
it does not regress as we seek to eliminate GLImage.

Note that GLImage is a start-from-0 refcounted type (i.e., the default),
for which the correct conversion from base::MakeRefCounted(...) when
making the constructor private with a friend class is
base::WrapRefCounted(new T(...)).

Bug: 1310018, 1382031
Change-Id: I52851f394f99661faef891469993b89b98b5a8f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4055102
Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1076757}

components/viz/test/test_image_factory.cc

@@ -18,10 +18,10 @@ namespace viz {
 
 namespace {
 
-class GLImageSharedMemory : public gl::GLImageMemory {
+class GLImageSharedMemory : public gl::GLImageMemoryForTesting {
  public:
   explicit GLImageSharedMemory(const gfx::Size& size)
-      : gl::GLImageMemory(size) {}
+      : gl::GLImageMemoryForTesting(size) {}
 
   GLImageSharedMemory(const GLImageSharedMemory&) = delete;
   GLImageSharedMemory& operator=(const GLImageSharedMemory&) = delete;

gpu/command_buffer/service/shared_image/shared_memory_image_backing.cc

@@ -139,7 +139,8 @@ SharedMemoryImageBacking::ProduceOverlay(SharedImageManager* manager,
   if (!shared_memory_wrapper_.IsValid())
     return nullptr;
 
-  auto gl_image = base::MakeRefCounted<gl::GLImageMemory>(size());
+  auto gl_image =
+      base::WrapRefCounted<gl::GLImageMemory>(new gl::GLImageMemory(size()));
   if (!gl_image->Initialize(shared_memory_wrapper_.GetMemory(),
                             ToBufferFormat(format()),
                             shared_memory_wrapper_.GetStride(),

ui/gl/direct_composition_surface_win_unittest.cc

@@ -43,10 +43,10 @@
 namespace gl {
 namespace {
 
-class GLImageRefCountedMemory : public GLImageMemory {
+class GLImageRefCountedMemory : public GLImageMemoryForTesting {
  public:
   explicit GLImageRefCountedMemory(const gfx::Size& size)
-      : GLImageMemory(size) {}
+      : GLImageMemoryForTesting(size) {}
 
   GLImageRefCountedMemory(const GLImageRefCountedMemory&) = delete;
   GLImageRefCountedMemory& operator=(const GLImageRefCountedMemory&) = delete;

ui/gl/gl_image_memory.cc

@@ -494,4 +494,9 @@ bool GLImageMemory::ValidFormat(gfx::BufferFormat format) {
   return false;
 }
 
+GLImageMemoryForTesting::GLImageMemoryForTesting(const gfx::Size& size)
+    : GLImageMemory(size) {}
+
+GLImageMemoryForTesting::~GLImageMemoryForTesting() = default;
+
 }  // namespace gl

ui/gl/gl_image_memory.h

@@ -14,14 +14,17 @@
 #include "ui/gfx/buffer_types.h"
 #include "ui/gl/gl_export.h"
 
+namespace gpu {
+class SharedMemoryImageBacking;
+}
+
 namespace gl {
 class GLContext;
+class GLImageMemoryForTesting;
 class GLSurface;
 
 class GL_EXPORT GLImageMemory : public GLImage {
  public:
-  explicit GLImageMemory(const gfx::Size& size);
-
   GLImageMemory(const GLImageMemory&) = delete;
   GLImageMemory& operator=(const GLImageMemory&) = delete;
 
@@ -55,6 +58,16 @@ class GL_EXPORT GLImageMemory : public GLImage {
   ~GLImageMemory() override;
 
  private:
+  // Make constructor private to ensure that only specified friend classes can
+  // create GLImageMemory instances.
+  explicit GLImageMemory(const gfx::Size& size);
+
+  // GLImageMemory should be created in production only by
+  // SharedMemoryImageBacking. Some tests need to subclass GLImageMemory in
+  // anonymous namespaces, for which GLImageMemoryForTesting exists.
+  friend class gpu::SharedMemoryImageBacking;
+  friend class GLImageMemoryForTesting;
+
   static bool ValidFormat(gfx::BufferFormat format);
 
   const gfx::Size size_;
@@ -70,6 +83,17 @@ class GL_EXPORT GLImageMemory : public GLImage {
   int memcpy_tasks_ = 0;
 };
 
+// GLImageMemoryForTesting supports test use cases for subclassing
+// GLImageMemory in anonymous namespaces. This class should never be used in
+// production.
+class GL_EXPORT GLImageMemoryForTesting : public GLImageMemory {
+ protected:
+  explicit GLImageMemoryForTesting(const gfx::Size& size);
+
+ protected:
+  ~GLImageMemoryForTesting() override;
+};
+
 }  // namespace gl
 
 #endif  // UI_GL_GL_IMAGE_MEMORY_H_