Throttle media decoding after excessive Android media server crashes

chrome/browser/android/media/media_throttle_infobar_delegate.cc

+// Copyright 2015 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 "chrome/browser/android/media/media_throttle_infobar_delegate.h"
+
+#include "chrome/browser/infobars/infobar_service.h"
+#include "chrome/grit/generated_resources.h"
+#include "components/infobars/core/infobar.h"
+#include "content/public/browser/web_contents.h"
+#include "grit/components_strings.h"
+#include "grit/theme_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "url/gurl.h"
+
+// static
+void MediaThrottleInfoBarDelegate::Create(
+    content::WebContents* web_contents,
+    const DecodeRequestGrantedCallback& callback) {
+  InfoBarService* infobar_service =
+      InfoBarService::FromWebContents(web_contents);
+  scoped_ptr<infobars::InfoBar> new_infobar(
+      infobar_service->CreateConfirmInfoBar(scoped_ptr<ConfirmInfoBarDelegate>(
+          new MediaThrottleInfoBarDelegate(callback))));
+
+  for (size_t i = 0; i < infobar_service->infobar_count(); ++i) {
+    infobars::InfoBar* old_infobar = infobar_service->infobar_at(i);
+    MediaThrottleInfoBarDelegate* delegate =
+        old_infobar->delegate()->AsMediaThrottleInfoBarDelegate();

[Ted C, 2015/10/01 02:19:56]

It's unfortunate to have to add AsMediaThrottleInfobarDelegate() to the base
delegate class just for this replacement case.

I wonder if this case would be better suited as a userdata on webcontents itself
that would just keep a ref to the infobar.  (added in the constructor, removed
in the destructor for this class).  With that said, I think this is a relatively
normal pattern, so I guess it's fine for this.

+    if (delegate != nullptr) {
+      infobar_service->ReplaceInfoBar(old_infobar, new_infobar.Pass());
+      return;
+    }
+  }
+
+  infobar_service->AddInfoBar(new_infobar.Pass());
+}
+
+MediaThrottleInfoBarDelegate::MediaThrottleInfoBarDelegate(
+    const DecodeRequestGrantedCallback& callback)
+    : decode_granted_callback_(callback) {
+}
+
+MediaThrottleInfoBarDelegate::~MediaThrottleInfoBarDelegate() {}
+
+MediaThrottleInfoBarDelegate*
+    MediaThrottleInfoBarDelegate::AsMediaThrottleInfoBarDelegate() {
+  return this;
+}
+
+base::string16 MediaThrottleInfoBarDelegate::GetMessageText() const {
+  return l10n_util::GetStringUTF16(IDS_MEDIA_THROTTLE_INFOBAR_TEXT);
+}
+
+base::string16 MediaThrottleInfoBarDelegate::GetButtonLabel(
+    InfoBarButton button) const {
+  return l10n_util::GetStringUTF16((button == BUTTON_OK) ?
+      IDS_MEDIA_THROTTLE_INFOBAR_ALLOW_BUTTON :
+      IDS_MEDIA_THROTTLE_INFOBAR_CANCEL_BUTTON);
+}
+
+bool MediaThrottleInfoBarDelegate::Accept() {
+  decode_granted_callback_.Run(true);
+  return true;
+}
+
+bool MediaThrottleInfoBarDelegate::Cancel() {
+  decode_granted_callback_.Run(false);
+  return true;
+}
+
+void MediaThrottleInfoBarDelegate::InfoBarDismissed() {

[Ted C, 2015/10/01 02:19:56]

Is this called if you close the tab?  Just wondering if we should run the
callback in the destructor as well to cover that case.

callback_helpers.h ResetAndReturn is nice if you want to run the callbacks and
be able to check whether they it is null in the destructor before running it
there.

+  decode_granted_callback_.Run(false);
+}