Fix implicit-fallthrough warnings. DO NOT MERGE.

These changes are not needed in goog/master.

Test: make checkbuild
Bug: 112564944
Change-Id: I75972e680c9502e1b83845f08e79b99a8084cc4c

libs/hwui/Caches.cpp

@@ -234,13 +234,13 @@ void Caches::flush(FlushMode mode) {
             gradientCache.clear();
             fontRenderer.clear();
             fboCache.clear();
-        // fall through
+            [[fallthrough]];
         case FlushMode::Moderate:
             fontRenderer.flush();
             textureCache.flush();
             pathCache.clear();
             tessellationCache.clear();
-        // fall through
+            [[fallthrough]];
         case FlushMode::Layers:
             renderBufferCache.clear();
             break;

libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp

@@ -331,7 +331,8 @@ sk_sp<Bitmap> SkiaOpenGLPipeline::allocateHardwareBitmap(renderthread::RenderThr
     switch (info.colorType()) {
         case kRGBA_8888_SkColorType:
             isSupported = true;
-        // ARGB_4444 is upconverted to RGBA_8888
+            // ARGB_4444 is upconverted to RGBA_8888
+            [[fallthrough]];
         case kARGB_4444_SkColorType:
             pixelFormat = PIXEL_FORMAT_RGBA_8888;
             format = GL_RGBA;