Bug 1250710 - Save and restore state, since this is used by WebGL. - r=ethlin

MozReview-Commit-ID: 3KZdIMpcRch

gfx/gl/GLBlitHelper.cpp

@@ -903,9 +903,13 @@ GLBlitHelper::BlitImageToFramebuffer(layers::Image* srcImage,
         return BlitGrallocImage(static_cast<layers::GrallocImage*>(srcImage));
 #endif
 
-    case ConvertPlanarYCbCr:
-        mGL->fPixelStorei(LOCAL_GL_UNPACK_ALIGNMENT, 1);
-        return BlitPlanarYCbCrImage(static_cast<PlanarYCbCrImage*>(srcImage));
+    case ConvertPlanarYCbCr: {
+            const auto saved = mGL->GetIntAs<GLint>(LOCAL_GL_UNPACK_ALIGNMENT);
+            mGL->fPixelStorei(LOCAL_GL_UNPACK_ALIGNMENT, 1);
+            const auto ret = BlitPlanarYCbCrImage(static_cast<PlanarYCbCrImage*>(srcImage));
+            mGL->fPixelStorei(LOCAL_GL_UNPACK_ALIGNMENT, saved);
+            return ret;
+        }
 
 #ifdef MOZ_WIDGET_ANDROID
     case ConvertSurfaceTexture: