Allow the topview in WebLayer to hide for non-committed navigations.

This matches Chrome in that the url bar is shown at the start of every navigation if it was hidden. It will stay visible for non committed navigations (again matching Chrome), but allows the user to scroll up to hide it.

Also fix this for the failed-load case.

Bug: 1127937
Change-Id: I6b91a1ae17a02f5340c5160f048b77d190e4b28d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2415673Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807996}

weblayer/browser/browser_controls_navigation_state_handler.cc

@@ -61,8 +61,10 @@ void BrowserControlsNavigationStateHandler::DidStartNavigation(
 void BrowserControlsNavigationStateHandler::DidFinishNavigation(
     content::NavigationHandle* navigation_handle) {
   if (navigation_handle->IsInMainFrame()) {
-    if (navigation_handle->HasCommitted())
-      is_showing_error_page_ = navigation_handle->IsErrorPage();
+    if (!navigation_handle->HasCommitted()) {
+      // There will be no DidFinishLoad or DidFailLoad, so hide the topview
+      ScheduleStopDelayedForceShow();
+    }
     delegate_->OnUpdateBrowserControlsStateBecauseOfProcessSwitch(
         navigation_handle->HasCommitted());
   }
@@ -81,6 +83,10 @@ void BrowserControlsNavigationStateHandler::DidFailLoad(
     content::RenderFrameHost* render_frame_host,
     const GURL& validated_url,
     int error_code) {
+  const bool is_main_frame =
+      render_frame_host->GetMainFrame() == render_frame_host;
+  if (is_main_frame)
+    ScheduleStopDelayedForceShow();
   if (render_frame_host->IsCurrent() &&
       (render_frame_host == web_contents()->GetMainFrame())) {
     UpdateState();

weblayer/browser/browser_controls_navigation_state_handler.h

@@ -82,9 +82,6 @@ class BrowserControlsNavigationStateHandler
   // Last value supplied to the delegate.
   base::Optional<content::BrowserControlsState> last_state_;
 
-  // True if an error page is showing.
-  bool is_showing_error_page_ = false;
-
   // This is cached as WebContents::IsCrashed() does not always return the
   // right thing.
   bool is_crashed_ = false;