Patch the Browser GDI crash with excessive downloads by restricting maximum number of downloads allowed at one time. When this limit is reached, we re-prompt the user.

BUG=39277
TEST=None

Review URL: http://codereview.chromium.org/1539002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43006 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 47 insertions, 9 deletions

diff --git a/chrome/browser/download/download_request_infobar_delegate.cc b/chrome/browser/download/download_request_infobar_delegate.cc
index 3a6aa5d..88c83fc 100644
--- a/chrome/browser/download/download_request_infobar_delegate.cc
+++ b/chrome/browser/download/download_request_infobar_delegate.cc
@@ -51,9 +51,9 @@ std::wstring DownloadRequestInfoBarDelegate::GetButtonLabel(
 bool DownloadRequestInfoBarDelegate::Accept() {
   if (host_) {
     host_->Accept();
-    host_ = NULL;
   }
-  return true;
+  // Accept() call will nullify host_ if no furthur prompts are required.
+  return !host_;
 }
 
 bool DownloadRequestInfoBarDelegate::Cancel() {
diff --git a/chrome/browser/download/download_request_manager.cc b/chrome/browser/download/download_request_manager.cc
index 4498233..9e86736 100644
--- a/chrome/browser/download/download_request_manager.cc
+++ b/chrome/browser/download/download_request_manager.cc
@@ -135,18 +135,37 @@ void DownloadRequestManager::TabDownloadState::Observe(
 }
 
 void DownloadRequestManager::TabDownloadState::NotifyCallbacks(bool allow) {
-  if (infobar_) {
-    // Reset the delegate so we don't get notified again.
-    infobar_->set_host(NULL);
-    infobar_ = NULL;
-  }
   status_ = allow ?
       DownloadRequestManager::ALLOW_ALL_DOWNLOADS :
       DownloadRequestManager::DOWNLOADS_NOT_ALLOWED;
   std::vector<DownloadRequestManager::Callback*> callbacks;
-  callbacks.swap(callbacks_);
-  for (size_t i = 0; i < callbacks.size(); ++i)
+  bool change_status = false;
+
+  // Selectively send first few notifications only if number of downloads exceed
+  // kMaxDownloadsAtOnce. In that case, we also retain the infobar instance and
+  // don't close it. If allow is false, we send all the notifications to cancel
+  // all remaining downloads and close the infobar.
+  if (!allow || (callbacks_.size() < kMaxDownloadsAtOnce)) {
+    if (infobar_) {
+      // Reset the delegate so we don't get notified again.
+      infobar_->set_host(NULL);
+      infobar_ = NULL;
+    }
+    callbacks.swap(callbacks_);
+  } else {
+    std::vector<DownloadRequestManager::Callback*>::iterator start, end;
+    start = callbacks_.begin();
+    end = callbacks_.begin() + kMaxDownloadsAtOnce;
+    callbacks.assign(start, end);
+    callbacks_.erase(start, end);
+    change_status = true;
+  }
+
+  for (size_t i = 0; i < callbacks.size(); ++i) {
     host_->ScheduleNotification(callbacks[i], allow);
+  }
+  if (change_status)
+    status_ = DownloadRequestManager::PROMPT_BEFORE_DOWNLOAD;
 }
 
 // DownloadRequestManager ------------------------------------------------------
@@ -247,7 +266,11 @@ void DownloadRequestManager::CanDownloadImpl(
       &effective_tab->controller(), &originating_tab->controller(), true);
   switch (state->download_status()) {
     case ALLOW_ALL_DOWNLOADS:
+      if (state->download_count() && !(state->download_count() %
+            DownloadRequestManager::kMaxDownloadsAtOnce))
+        state->set_download_status(PROMPT_BEFORE_DOWNLOAD);
       ScheduleNotification(callback, true);
+      state->increment_download_count();
       break;
 
     case ALLOW_ONE_DOWNLOAD:
@@ -261,6 +284,7 @@ void DownloadRequestManager::CanDownloadImpl(
 
     case PROMPT_BEFORE_DOWNLOAD:
       state->PromptUserForDownload(effective_tab, callback);
+      state->increment_download_count();
       break;
 
     default:
diff --git a/chrome/browser/download/download_request_manager.h b/chrome/browser/download/download_request_manager.h
index cea0536..97fa7f8 100644
--- a/chrome/browser/download/download_request_manager.h
+++ b/chrome/browser/download/download_request_manager.h
@@ -51,6 +51,9 @@ class DownloadRequestManager
     DOWNLOADS_NOT_ALLOWED
   };
 
+  // Max number of downloads before a "Prompt Before Download" Dialog is shown.
+  static const size_t kMaxDownloadsAtOnce = 50;
+
   // The callback from CanDownloadOnIOThread. This is invoked on the io thread.
   class Callback {
    public:
@@ -87,6 +90,14 @@ class DownloadRequestManager
       return status_;
     }
 
+    // Number of "ALLOWED" downloads.
+    void increment_download_count() {
+      download_count_++;
+    }
+    size_t download_count() const {
+      return download_count_;
+    }
+
     // Invoked when a user gesture occurs (mouse click, enter or space). This
     // may result in invoking Remove on DownloadRequestManager.
     void OnUserGesture();
@@ -114,6 +125,7 @@ class DownloadRequestManager
         : host_(NULL),
           controller_(NULL),
           status_(DownloadRequestManager::ALLOW_ONE_DOWNLOAD),
+          download_count_(0),
           infobar_(NULL) {
     }
 
@@ -136,6 +148,8 @@ class DownloadRequestManager
 
     DownloadRequestManager::DownloadStatus status_;
 
+    size_t download_count_;
+
     // Callbacks we need to notify. This is only non-empty if we're showing a
     // dialog.
     // See description above CanDownloadOnIOThread for details on lifetime of