Update a webview plugin's WebView's lifecycle immediately after resizing.

components/plugins/renderer/webview_plugin.cc

Index: components/plugins/renderer/webview_plugin.cc
diff --git a/components/plugins/renderer/webview_plugin.cc b/components/plugins/renderer/webview_plugin.cc
index b6ddb46033241a3afc3a2cc15e12b7bbfd70179a..05611db29fa03b22b96bc626c86907cd498d2485 100644
--- a/components/plugins/renderer/webview_plugin.cc
+++ b/components/plugins/renderer/webview_plugin.cc
@@ -57,7 +57,8 @@ WebViewPlugin::WebViewPlugin(content::RenderView* render_view,
       web_view_(WebView::create(this)),
       finished_loading_(false),
       focused_(false),
-      is_painting_(false) {
+      is_painting_(false),
+      is_resizing_(false) {
   // ApplyWebPreferences before making a WebLocalFrame so that the frame sees a
   // consistent view of our preferences.
   content::RenderView::ApplyWebPreferences(preferences, web_view_);
@@ -199,14 +200,22 @@ void WebViewPlugin::updateGeometry(const WebRect& window_rect,
                                    const WebRect& unobscured_rect,
                                    const WebVector<WebRect>& cut_outs_rects,
                                    bool is_visible) {
+  base::AutoReset<bool> is_resizing(
+        &is_resizing_, true);
+
   if (static_cast<gfx::Rect>(window_rect) != rect_) {
     rect_ = window_rect;
     WebSize newSize(window_rect.width, window_rect.height);
     web_view_->resize(newSize);
   }
 
-  if (delegate_)
+  if (delegate_) {
     delegate_->OnUnobscuredRectUpdate(gfx::Rect(unobscured_rect));
+    // The delegate may have dirtied style and layout of the WebView.
+    // See for example the resizePoster function in plugin_poster.html.
+    // Run the lifecycle now so that it is clean.
+    web_view_->updateAllLifecyclePhases();

[leviw_travelin_and_unemployed, 2016/03/04 19:24:58]

When all you've got is a hammer :p

+  }
 }
 
 void WebViewPlugin::updateFocus(bool focused, blink::WebFocusType focus_type) {
@@ -293,6 +302,14 @@ void WebViewPlugin::didChangeCursor(const WebCursorInfo& cursor) {
 }
 
 void WebViewPlugin::scheduleAnimation() {
+  // Resizes must be self-contained: any lifecycle updating must
+  // be triggerd from within the WebView or this WebViewPlugin.
+  // This is because this WebViewPlugin is contained in another
+  // Web View which may be in the middle of updating its lifecycle,
+  // but after layout is done, and it is illegal to dirty earlier
+  // lifecycle stages during later ones.
+  if (is_resizing_)
+    return;
   if (container_) {
     // This should never happen; see also crbug.com/545039 for context.
     CHECK(!is_painting_);