Bug 1665815 - Avoid using scissored glClear() on Android Emulator with SwiftShader r=geckoview-reviewers,jnicol,agi

Emulator with SwiftShader is buggy when attempting to clear picture cache textures with a scissor rect set.

Differential Revision: https://phabricator.services.mozilla.com/D90644

widget/android/GfxInfo.cpp

@@ -599,6 +599,22 @@ nsresult GfxInfo::GetFeatureStatusImpl(
       }
       return NS_OK;
     }
+
+    if (aFeature == FEATURE_WEBRENDER_SCISSORED_CACHE_CLEARS) {
+      // Emulator with SwiftShader is buggy when attempting to clear picture
+      // cache textures with a scissor rect set.
+      const bool isEmulatorSwiftShader =
+          mGLStrings->Renderer().Find(
+              "Android Emulator OpenGL ES Translator (Google SwiftShader)") >=
+          0;
+      if (isEmulatorSwiftShader) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_BUG_1603515";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
   }
 
   return GfxInfoBase::GetFeatureStatusImpl(