gpu: workaround force_cube_map_positive_x_allocation fixes Android crash.

gpu/command_buffer/service/texture_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/texture_manager.h"
 
 #include <algorithm>
 #include <set>
 #include <utility>
 
@@ skipping 1921 matching lines @@
     DecoderTextureState* texture_state,
     ContextState* state,
     DecoderFramebufferState* framebuffer_state,
     const char* function_name,
     const DoTexImageArguments& args) {
   TextureRef* texture_ref;
   if (!ValidateTexImage(state, function_name, args, &texture_ref)) {
     return;
   }
 
+  if (texture_state->force_cube_map_positive_x_allocation) {
+    DoTexImage2DCubeMapPositiveXIfNeeded(texture_state, state->GetErrorState(),
+                                         framebuffer_state, function_name,
+                                         texture_ref, args);
+  }
+
   DoTexImage(texture_state, state->GetErrorState(), framebuffer_state,
              function_name, texture_ref, args);
 }
 
 GLenum TextureManager::AdjustTexFormat(GLenum format) const {
   // TODO(bajones): GLES 3 allows for internal format and format to differ.
   // This logic may need to change as a result.
   if (gfx::GetGLImplementation() == gfx::kGLImplementationDesktopGL) {
     if (format == GL_SRGB_EXT)
       return GL_RGB;
     if (format == GL_SRGB_ALPHA_EXT)
       return GL_RGBA;
   }
   return format;
 }
 
+// Nexus 5 crashes on allocating a cube map texture bound to FBO, if
+// the CUBE_MAP_POSITIVE_X texture is not allocated yet.
+void TextureManager::DoTexImage2DCubeMapPositiveXIfNeeded(
+    DecoderTextureState* texture_state,
+    ErrorState* error_state,
+    DecoderFramebufferState* framebuffer_state,
+    const char* function_name,
+    TextureRef* texture_ref,
+    const DoTexImageArguments& args) {
+  switch (args.target) {
+    case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
+    case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
+    case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
+    case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
+    case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
+      break;
+    default:
+      return;
+  }
+
+  // ValidateTexImage is passed already.
+  Texture* texture = texture_ref->texture();
+  int width = 0;
+  int height = 0;
+  bool positive_x_level_defined = texture->GetLevelSize(
+      GL_TEXTURE_CUBE_MAP_POSITIVE_X, args.level, &width, &height, nullptr);
+  if (!positive_x_level_defined) {
+    DoTexImageArguments positive_x_args = args;

[no sievers, 2015/08/11 21:07:39]

I don't think we should use the pixels passed in with this API call to allocate
the pos_x face.
Can we maybe just use ClearLevel()? Then it would also take care of the clearing
logic and other potential redundant uploads.

[dshwang, 2015/08/12 08:06:09]

Good point. I'll reset pixels to nullptr like regular glTexImage(nullptr).
In nullptr case, TextureManager marks "unclear" to the texture, and then will
clear the texture later if needed.
We can not use ClearLevel(). ClearLevel() requires that the texture is defined.
we want to define the texture here. ClearLevel() attaches the texture to temp
FBO, and then calls glClear().

[no sievers, 2015/08/12 18:54:05]

I don't think it's true that it needs to be complete, see all the call sites to
ClearTextureLevel() from the decoder. Also it only does the glClear() if it's a
depth format as a workaround for Angle.

[dshwang, 2015/08/13 09:12:35]

Yes, I incorrectly explained the implementation detail. In general case,
glTexSubImage2D is used to clear the texture.
Anyway, the important point is that ClearLevel() doesn't call glTexImage2D.
ClearLevel() just clear the given texture. We need to define new texture here.

+    positive_x_args.target = GL_TEXTURE_CUBE_MAP_POSITIVE_X;
+    DoTexImage(texture_state, error_state, framebuffer_state, function_name,
+               texture_ref, positive_x_args);
+  }
+}
+
 void TextureManager::DoTexImage(
     DecoderTextureState* texture_state,
     ErrorState* error_state,
     DecoderFramebufferState* framebuffer_state,
     const char* function_name,
     TextureRef* texture_ref,
     const DoTexImageArguments& args) {
   Texture* texture = texture_ref->texture();
   GLsizei tex_width = 0;
   GLsizei tex_height = 0;
@@ skipping 131 matching lines @@
   // The link to the memory tracking |client_id| is given a higher importance
   // than other refs.
   if (ref == ref->texture()->memory_tracking_ref_)
     importance = 2;
 
   pmd->AddOwnershipEdge(client_guid, service_guid, importance);
 }
 
 }  // namespace gles2
 }  // namespace gpu