Bug 1322650 - Support a 'continuous' mode for SurfaceTexture r=jgilbert

This is needed to support Flash on Android

MozReview-Commit-ID: 5yNIoZHonla

gfx/layers/opengl/TextureHostOGL.cpp

@@ -62,7 +62,8 @@ CreateTextureHostOGL(const SurfaceDescriptor& aDesc,
 
       result = new SurfaceTextureHost(aFlags,
                                       surfaceTexture,
-                                      desc.size());
+                                      desc.size(),
+                                      desc.continuous());
       break;
     }
 #endif
@@ -411,11 +412,15 @@ SurfaceTextureSource::DeallocateDeviceData()
 
 SurfaceTextureHost::SurfaceTextureHost(TextureFlags aFlags,
                                        mozilla::java::GeckoSurfaceTexture::Ref& aSurfTex,
-                                       gfx::IntSize aSize)
+                                       gfx::IntSize aSize,
+                                       bool aContinuousUpdate)
   : TextureHost(aFlags)
   , mSurfTex(aSurfTex)
   , mSize(aSize)
+  , mContinuousUpdate(aContinuousUpdate)
 {
+  // Continuous update makes no sense with single buffer mode
+  MOZ_ASSERT(!mSurfTex->IsSingleBuffer() || !mContinuousUpdate);
 }
 
 SurfaceTextureHost::~SurfaceTextureHost()
@@ -430,9 +435,13 @@ SurfaceTextureHost::PrepareTextureSource(CompositableTextureSourceRef& aTexture)
     return;
   }
 
-  // This advances the SurfaceTexture's internal buffer queue. We only want to do this
-  // once per transaction. We can then composite that texture as many times as needed.
-  mSurfTex->UpdateTexImage();
+  if (!mContinuousUpdate) {
+    // UpdateTexImage() advances the internal buffer queue, so we only want to call this
+    // once per transactionwhen we are not in continuous mode (as we are here). Otherwise,
+    // the SurfaceTexture content will be de-synced from the rest of the page in subsequent
+    // compositor passes.
+    mSurfTex->UpdateTexImage();
+  }
 }
 
 gl::GLContext*
@@ -450,6 +459,10 @@ SurfaceTextureHost::Lock()
     return false;
   }
 
+  if (mContinuousUpdate) {
+    mSurfTex->UpdateTexImage();
+  }
+
   if (!mTextureSource) {
     gfx::SurfaceFormat format = gfx::SurfaceFormat::R8G8B8A8;
     GLenum target = LOCAL_GL_TEXTURE_EXTERNAL; // This is required by SurfaceTexture