blink: Make WebMainThreadScrollingReason wrap the cc enum.

cc/blink/web_layer_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/blink/web_layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 327 matching lines @@
 }
 
 void WebLayerImpl::setHaveScrollEventHandlers(bool have_scroll_event_handlers) {
   layer_->SetHaveScrollEventHandlers(have_scroll_event_handlers);
 }
 
 bool WebLayerImpl::haveScrollEventHandlers() const {
   return layer_->have_scroll_event_handlers();
 }
 
-static_assert(blink::WebMainThreadScrollingReason::NotScrollingOnMain ==
-                  cc::MainThreadScrollingReason::kNotScrollingOnMain,
-              "MainThreadScrollingReason and "
-              "WebMainThreadScrollingReason enums must match");
-static_assert(
-    blink::WebMainThreadScrollingReason::HasBackgroundAttachmentFixedObjects ==
-        cc::MainThreadScrollingReason::kHasBackgroundAttachmentFixedObjects,
-    "MainThreadScrollingReason and "
-    "WebMainThreadScrollingReason enums must match");
-static_assert(
-    blink::WebMainThreadScrollingReason::
-            HasNonLayerViewportConstrainedObjects ==
-        cc::MainThreadScrollingReason::kHasNonLayerViewportConstrainedObjects,
-    "MainThreadScrollingReason and "
-    "WebMainThreadScrollingReason enums must match");
-static_assert(
-
-    blink::WebMainThreadScrollingReason::ThreadedScrollingDisabled ==
-        cc::MainThreadScrollingReason::kThreadedScrollingDisabled,
-    "MainThreadScrollingReason and "
-    "WebMainThreadScrollingReason enums must match");
-static_assert(blink::WebMainThreadScrollingReason::ScrollBarScrolling ==
-                  cc::MainThreadScrollingReason::kScrollbarScrolling,
-              "MainThreadScrollingReason and "
-              "WebMainThreadScrollingReason enums must match");
-static_assert(blink::WebMainThreadScrollingReason::PageOverlay ==
-                  cc::MainThreadScrollingReason::kPageOverlay,
-              "MainThreadScrollingReason and "
-              "WebMainThreadScrollingReason enums must match");
-
 void WebLayerImpl::addMainThreadScrollingReasons(
-    blink::WebMainThreadScrollingReason::WebMainThreadScrollingReason
-        main_thread_scrolling_reasons) {
+    uint32_t main_thread_scrolling_reasons) {
   DCHECK(main_thread_scrolling_reasons);
   // WebLayerImpl should only know about non-transient scrolling
   // reasons. Transient scrolling reasons are computed per hit test.
-  DCHECK_LE(
-      main_thread_scrolling_reasons,
-      static_cast<
-          blink::WebMainThreadScrollingReason::WebMainThreadScrollingReason>(
-          cc::MainThreadScrollingReason::kMaxNonTransientScrollingReason));
+  // TODO(tdresser): This is comparing less than a bit flag but that's not valid

[danakj, 2016/01/20 00:04:35]

tdresser please take a look at this, it appears to be mighty sketchy code (in
TOT).

+  // if there is more than one reason given in |main_thread_scrolling_reasons|.
+  DCHECK_LE(main_thread_scrolling_reasons,
+            cc::MainThreadScrollingReason::kMaxNonTransientScrollingReason);
   layer_->AddMainThreadScrollingReasons(main_thread_scrolling_reasons);
 }
 
 void WebLayerImpl::clearMainThreadScrollingReasons() {
   layer_->ClearMainThreadScrollingReasons();
 }
 
 bool WebLayerImpl::shouldScrollOnMainThread() const {
   return layer_->should_scroll_on_main_thread();
 }
@@ skipping 213 matching lines @@
 
 Layer* WebLayerImpl::layer() const {
   return layer_.get();
 }
 
 void WebLayerImpl::SetContentsOpaqueIsFixed(bool fixed) {
   contents_opaque_is_fixed_ = fixed;
 }
 
 }  // namespace cc_blink