Revert of Plugin Power Saver: Remove Size Recheck hack in plugin placeholders.

components/plugins/renderer/loadable_plugin_placeholder.cc

Index: components/plugins/renderer/loadable_plugin_placeholder.cc
diff --git a/components/plugins/renderer/loadable_plugin_placeholder.cc b/components/plugins/renderer/loadable_plugin_placeholder.cc
index b13ece52396a57c5836c5fccfeb0906e77cbe439..f28c19638b980491014f7c72e410f0150bc2ad3b 100644
--- a/components/plugins/renderer/loadable_plugin_placeholder.cc
+++ b/components/plugins/renderer/loadable_plugin_placeholder.cc
@@ -4,6 +4,7 @@
 
 #include "components/plugins/renderer/loadable_plugin_placeholder.h"
 
+#include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/json/string_escape.h"
@@ -34,6 +35,11 @@
 
 namespace plugins {
 
+// TODO(tommycli): After a size update, re-check the size after this delay, as
+// Blink can report incorrect sizes to plugins while the compositing state is
+// dirty. Chosen because it seems to work.
+const int kSizeChangeRecheckDelayMilliseconds = 100;
+
 void LoadablePluginPlaceholder::BlockForPowerSaverPoster() {
   DCHECK(!is_blocked_for_power_saver_poster_);
   is_blocked_for_power_saver_poster_ = true;
@@ -65,6 +71,7 @@
       premade_throttler_(nullptr),
       allow_loading_(false),
       finished_loading_(false),
+      in_size_recheck_(false),
       heuristic_run_before_(premade_throttler_ != nullptr),
       weak_factory_(this) {}
 
@@ -183,13 +190,160 @@
 void LoadablePluginPlaceholder::OnUnobscuredRectUpdate(
     const gfx::Rect& unobscured_rect) {
   DCHECK(content::RenderThread::Get());
-  if (!plugin() || !power_saver_enabled_ || !finished_loading_)
-    return;
-
-  if (unobscured_rect_ == unobscured_rect)
-    return;
-
-  unobscured_rect_ = unobscured_rect;
+  if (!power_saver_enabled_ || !finished_loading_)
+    return;
+
+  // Only update the unobscured rect during the recheck phase. Also early exit
+  // to prevent reentrancy issues.
+  if (in_size_recheck_) {
+    unobscured_rect_ = unobscured_rect;
+    return;
+  }
+
+  if (!size_update_timer_.IsRunning()) {
+    // TODO(tommycli): We have to post a delayed task to recheck the size, as
+    // Blink can report wrong sizes for partially obscured plugins while the
+    // compositing state is dirty. https://crbug.com/343769
+    size_update_timer_.Start(
+        FROM_HERE,
+        base::TimeDelta::FromMilliseconds(kSizeChangeRecheckDelayMilliseconds),
+        base::Bind(&LoadablePluginPlaceholder::RecheckSizeAndMaybeUnthrottle,
+                   weak_factory_.GetWeakPtr()));
+  }
+}
+
+void LoadablePluginPlaceholder::WasShown() {
+  if (is_blocked_for_background_tab_) {
+    is_blocked_for_background_tab_ = false;
+    if (!LoadingBlocked())
+      LoadPlugin();
+  }
+}
+
+void LoadablePluginPlaceholder::OnLoadBlockedPlugins(
+    const std::string& identifier) {
+  if (!identifier.empty() && identifier != identifier_)
+    return;
+
+  RenderThread::Get()->RecordAction(UserMetricsAction("Plugin_Load_UI"));
+  LoadPlugin();
+}
+
+void LoadablePluginPlaceholder::OnSetIsPrerendering(bool is_prerendering) {
+  // Prerendering can only be enabled prior to a RenderView's first navigation,
+  // so no BlockedPlugin should see the notification that enables prerendering.
+  DCHECK(!is_prerendering);
+  if (is_blocked_for_prerendering_) {
+    is_blocked_for_prerendering_ = false;
+    if (!LoadingBlocked())
+      LoadPlugin();
+  }
+}
+
+void LoadablePluginPlaceholder::LoadPlugin() {
+  // This is not strictly necessary but is an important defense in case the
+  // event propagation changes between "close" vs. "click-to-play".
+  if (hidden())
+    return;
+  if (!plugin())
+    return;
+  if (!allow_loading_) {
+    NOTREACHED();
+    return;
+  }
+
+  if (premade_throttler_) {
+    premade_throttler_->SetHiddenForPlaceholder(false /* hidden */);
+    ReplacePlugin(premade_throttler_->GetWebPlugin());
+    premade_throttler_ = nullptr;
+  } else {
+    ReplacePlugin(CreatePlugin());
+  }
+}
+
+void LoadablePluginPlaceholder::LoadCallback() {
+  RenderThread::Get()->RecordAction(UserMetricsAction("Plugin_Load_Click"));
+  // If the user specifically clicks on the plugin content's placeholder,
+  // disable power saver throttling for this instance.
+  MarkPluginEssential(PluginInstanceThrottler::UNTHROTTLE_METHOD_BY_CLICK);
+  LoadPlugin();
+}
+
+void LoadablePluginPlaceholder::DidFinishLoadingCallback() {
+  finished_loading_ = true;
+  if (message_.length() > 0)
+    UpdateMessage();
+
+  // Wait for the placeholder to finish loading to hide the premade plugin.
+  // This is necessary to prevent a flicker.
+  if (premade_throttler_ && power_saver_enabled_)
+    premade_throttler_->SetHiddenForPlaceholder(true /* hidden */);
+
+  // In case our initial geometry was reported before the placeholder finished
+  // loading, request another one. Needed for correct large poster unthrottling.
+  if (plugin()) {
+    CHECK(plugin()->container());
+    plugin()->container()->reportGeometry();
+  }
+}
+
+void LoadablePluginPlaceholder::DidFinishIconRepositionForTestingCallback() {
+  // Set an attribute and post an event, so browser tests can wait for the
+  // placeholder to be ready to receive simulated user input.
+  blink::WebElement element = plugin()->container()->element();
+  element.setAttribute("placeholderReady", "true");
+
+  scoped_ptr<content::V8ValueConverter> converter(
+      content::V8ValueConverter::create());
+  base::StringValue value("placeholderReady");
+  blink::WebSerializedScriptValue message_data =
+      blink::WebSerializedScriptValue::serialize(converter->ToV8Value(
+          &value, element.document().frame()->mainWorldScriptContext()));
+  blink::WebDOMMessageEvent msg_event(message_data);
+
+  element.dispatchEvent(msg_event);
+}
+
+void LoadablePluginPlaceholder::SetPluginInfo(
+    const content::WebPluginInfo& plugin_info) {
+  plugin_info_ = plugin_info;
+}
+
+const content::WebPluginInfo& LoadablePluginPlaceholder::GetPluginInfo() const {
+  return plugin_info_;
+}
+
+void LoadablePluginPlaceholder::SetIdentifier(const std::string& identifier) {
+  identifier_ = identifier;
+}
+
+const std::string& LoadablePluginPlaceholder::GetIdentifier() const {
+  return identifier_;
+}
+
+bool LoadablePluginPlaceholder::LoadingBlocked() const {
+  DCHECK(allow_loading_);
+  return is_blocked_for_background_tab_ || is_blocked_for_power_saver_poster_ ||
+         is_blocked_for_prerendering_;
+}
+
+void LoadablePluginPlaceholder::RecheckSizeAndMaybeUnthrottle() {
+  DCHECK(content::RenderThread::Get());
+  DCHECK(!in_size_recheck_);
+  DCHECK(finished_loading_);
+
+  base::AutoReset<bool> recheck_scope(&in_size_recheck_, true);
+
+  if (!plugin())
+    return;
+
+  gfx::Rect old_rect = unobscured_rect_;
+
+  // Re-check the size in case the reported size was incorrect.
+  plugin()->container()->reportGeometry();
+
+  if (old_rect == unobscured_rect_)
+    return;
 
   float zoom_factor = plugin()->container()->pageZoomFactor();
   int width = roundf(unobscured_rect_.width() / zoom_factor);
@@ -228,119 +382,4 @@
   }
 }
 
-void LoadablePluginPlaceholder::WasShown() {
-  if (is_blocked_for_background_tab_) {
-    is_blocked_for_background_tab_ = false;
-    if (!LoadingBlocked())
-      LoadPlugin();
-  }
-}
-
-void LoadablePluginPlaceholder::OnLoadBlockedPlugins(
-    const std::string& identifier) {
-  if (!identifier.empty() && identifier != identifier_)
-    return;
-
-  RenderThread::Get()->RecordAction(UserMetricsAction("Plugin_Load_UI"));
-  LoadPlugin();
-}
-
-void LoadablePluginPlaceholder::OnSetIsPrerendering(bool is_prerendering) {
-  // Prerendering can only be enabled prior to a RenderView's first navigation,
-  // so no BlockedPlugin should see the notification that enables prerendering.
-  DCHECK(!is_prerendering);
-  if (is_blocked_for_prerendering_) {
-    is_blocked_for_prerendering_ = false;
-    if (!LoadingBlocked())
-      LoadPlugin();
-  }
-}
-
-void LoadablePluginPlaceholder::LoadPlugin() {
-  // This is not strictly necessary but is an important defense in case the
-  // event propagation changes between "close" vs. "click-to-play".
-  if (hidden())
-    return;
-  if (!plugin())
-    return;
-  if (!allow_loading_) {
-    NOTREACHED();
-    return;
-  }
-
-  if (premade_throttler_) {
-    premade_throttler_->SetHiddenForPlaceholder(false /* hidden */);
-    ReplacePlugin(premade_throttler_->GetWebPlugin());
-    premade_throttler_ = nullptr;
-  } else {
-    ReplacePlugin(CreatePlugin());
-  }
-}
-
-void LoadablePluginPlaceholder::LoadCallback() {
-  RenderThread::Get()->RecordAction(UserMetricsAction("Plugin_Load_Click"));
-  // If the user specifically clicks on the plugin content's placeholder,
-  // disable power saver throttling for this instance.
-  MarkPluginEssential(PluginInstanceThrottler::UNTHROTTLE_METHOD_BY_CLICK);
-  LoadPlugin();
-}
-
-void LoadablePluginPlaceholder::DidFinishLoadingCallback() {
-  finished_loading_ = true;
-  if (message_.length() > 0)
-    UpdateMessage();
-
-  // Wait for the placeholder to finish loading to hide the premade plugin.
-  // This is necessary to prevent a flicker.
-  if (premade_throttler_ && power_saver_enabled_)
-    premade_throttler_->SetHiddenForPlaceholder(true /* hidden */);
-
-  // In case our initial geometry was reported before the placeholder finished
-  // loading, request another one. Needed for correct large poster unthrottling.
-  if (plugin()) {
-    CHECK(plugin()->container());
-    plugin()->container()->reportGeometry();
-  }
-}
-
-void LoadablePluginPlaceholder::DidFinishIconRepositionForTestingCallback() {
-  // Set an attribute and post an event, so browser tests can wait for the
-  // placeholder to be ready to receive simulated user input.
-  blink::WebElement element = plugin()->container()->element();
-  element.setAttribute("placeholderReady", "true");
-
-  scoped_ptr<content::V8ValueConverter> converter(
-      content::V8ValueConverter::create());
-  base::StringValue value("placeholderReady");
-  blink::WebSerializedScriptValue message_data =
-      blink::WebSerializedScriptValue::serialize(converter->ToV8Value(
-          &value, element.document().frame()->mainWorldScriptContext()));
-  blink::WebDOMMessageEvent msg_event(message_data);
-
-  element.dispatchEvent(msg_event);
-}
-
-void LoadablePluginPlaceholder::SetPluginInfo(
-    const content::WebPluginInfo& plugin_info) {
-  plugin_info_ = plugin_info;
-}
-
-const content::WebPluginInfo& LoadablePluginPlaceholder::GetPluginInfo() const {
-  return plugin_info_;
-}
-
-void LoadablePluginPlaceholder::SetIdentifier(const std::string& identifier) {
-  identifier_ = identifier;
-}
-
-const std::string& LoadablePluginPlaceholder::GetIdentifier() const {
-  return identifier_;
-}
-
-bool LoadablePluginPlaceholder::LoadingBlocked() const {
-  DCHECK(allow_loading_);
-  return is_blocked_for_background_tab_ || is_blocked_for_power_saver_poster_ ||
-         is_blocked_for_prerendering_;
-}
-
 }  // namespace plugins