Correctly track texture cleared state for sharing

When sharing textures in mailboxes using MailboxManagerSync
there's an optimization that if textures are not updated then
there is no need to share it again. However the code that
checks whether textures are updated ignores the cleared
state, causing shared texture to remain uncleared
indefinitely.

Fix by check the cleared state. And add a unit test.

BUG=453199

Review URL: https://codereview.chromium.org/890453002

Cr-Commit-Position: refs/heads/master@{#313814}

gpu/command_buffer/service/mailbox_manager_unittest.cc

@@ -72,6 +72,13 @@ class MailboxManagerTest : public GpuServiceTest {
                           cleared);
   }
 
+  void SetLevelCleared(Texture* texture,
+                       GLenum target,
+                       GLint level,
+                       bool cleared) {
+    texture->SetLevelCleared(target, level, cleared);
+  }
+
   GLenum SetParameter(Texture* texture, GLenum pname, GLint param) {
     return texture->SetParameteri(feature_info_.get(), pname, param);
   }
@@ -543,6 +550,51 @@ TEST_F(MailboxManagerSyncTest, ProduceAndClobber) {
   EXPECT_EQ(NULL, manager2_->ConsumeTexture(name));
 }
 
+TEST_F(MailboxManagerSyncTest, ClearedStateSynced) {
+  const GLuint kNewTextureId = 1234;
+
+  Texture* texture = DefineTexture();
+  EXPECT_TRUE(texture->SafeToRenderFrom());
+
+  Mailbox name = Mailbox::Generate();
+
+  manager_->ProduceTexture(name, texture);
+  EXPECT_EQ(texture, manager_->ConsumeTexture(name));
+
+  // Synchronize
+  manager_->PushTextureUpdates(0);
+  manager2_->PullTextureUpdates(0);
+
+  EXPECT_CALL(*gl_, GenTextures(1, _))
+      .WillOnce(SetArgPointee<1>(kNewTextureId));
+  SetupUpdateTexParamExpectations(
+      kNewTextureId, GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT);
+  Texture* new_texture = manager2_->ConsumeTexture(name);
+  EXPECT_FALSE(new_texture == NULL);
+  EXPECT_NE(texture, new_texture);
+  EXPECT_EQ(kNewTextureId, new_texture->service_id());
+  EXPECT_TRUE(texture->SafeToRenderFrom());
+
+  // Change cleared to false.
+  SetLevelCleared(texture, texture->target(), 0, false);
+  EXPECT_FALSE(texture->SafeToRenderFrom());
+
+  // Synchronize
+  manager_->PushTextureUpdates(0);
+  SetupUpdateTexParamExpectations(
+      kNewTextureId, GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT);
+  manager2_->PullTextureUpdates(0);
+
+  // Cleared state should be synced.
+  EXPECT_FALSE(new_texture->SafeToRenderFrom());
+
+  DestroyTexture(texture);
+  DestroyTexture(new_texture);
+
+  EXPECT_EQ(NULL, manager_->ConsumeTexture(name));
+  EXPECT_EQ(NULL, manager2_->ConsumeTexture(name));
+}
+
 // Putting the same texture into multiple mailboxes should result in sharing
 // only a single texture also within a synchronized manager instance.
 TEST_F(MailboxManagerSyncTest, SharedThroughMultipleMailboxes) {

gpu/command_buffer/service/texture_definition.cc

@@ -413,7 +413,8 @@ bool TextureDefinition::Matches(const Texture* texture) const {
   if (texture->min_filter_ != min_filter_ ||
       texture->mag_filter_ != mag_filter_ ||
       texture->wrap_s_ != wrap_s_ ||
-      texture->wrap_t_ != wrap_t_) {
+      texture->wrap_t_ != wrap_t_ ||
+      texture->SafeToRenderFrom() != SafeToRenderFrom()) {
     return false;
   }
 
@@ -424,5 +425,16 @@ bool TextureDefinition::Matches(const Texture* texture) const {
   return true;
 }
 
+bool TextureDefinition::SafeToRenderFrom() const {
+  for (const std::vector<LevelInfo>& face_info : level_infos_) {
+    for (const LevelInfo& level_info : face_info) {
+      if (!level_info.cleared) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
 }  // namespace gles2
 }  // namespace gpu

gpu/command_buffer/service/texture_definition.h

@@ -58,6 +58,8 @@ class TextureDefinition {
   scoped_refptr<NativeImageBuffer> image() const { return image_buffer_; }
 
  private:
+  bool SafeToRenderFrom() const;
+
   struct LevelInfo {
     LevelInfo(GLenum target,
               GLenum internal_format,