Reign in print throttling.

Don't throttle the frequency of calls to window.print() from JavaScript if the
action was user initiated (e.g., clicking on a button), if print preview is
active (which is tab-modal, so the user can easily stop any attempted DOS), or
if a flag on the command line is given (say, you want to run chromium for a
point-of-sale system).

BUG=50186
TEST=Go to a web page with a print button - should be able to click on the button and cancel the print quickly without ever seeing the dreaded warning from 50186 in the console.


Review URL: https://chromiumcodereview.appspot.com/10890054

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@157612 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 19 insertions, 4 deletions

diff --git a/chrome/renderer/print_web_view_helper.cc b/chrome/renderer/print_web_view_helper.cc
index ccf7789..5ba2c80 100644
--- a/chrome/renderer/print_web_view_helper.cc
+++ b/chrome/renderer/print_web_view_helper.cc
@@ -527,6 +527,11 @@ bool IsPrintPreviewEnabled() {
       switches::kRendererPrintPreview);
 }
 
+bool IsPrintThrottlingDisabled() {
+  return CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kDisableScriptedPrintThrottling);
+}
+
 }  // namespace
 
 // static - Not anonymous so that platform implementations can use it.
@@ -717,6 +722,7 @@ PrintWebViewHelper::PrintWebViewHelper(content::RenderView* render_view)
       content::RenderViewObserverTracker<PrintWebViewHelper>(render_view),
       print_web_view_(NULL),
       is_preview_enabled_(IsPrintPreviewEnabled()),
+      is_scripted_print_throttling_disabled_(IsPrintThrottlingDisabled()),
       is_print_ready_metafile_sent_(false),
       ignore_css_margins_(false),
       user_cancelled_scripted_print_count_(0),
@@ -728,14 +734,23 @@ PrintWebViewHelper::PrintWebViewHelper(content::RenderView* render_view)
 PrintWebViewHelper::~PrintWebViewHelper() {}
 
 bool PrintWebViewHelper::IsScriptInitiatedPrintAllowed(
-    WebKit::WebFrame* frame) {
+    WebKit::WebFrame* frame, bool user_initiated) {
   if (is_scripted_printing_blocked_)
     return false;
-  return !IsScriptInitiatedPrintTooFrequent(frame);
+  // If preview is enabled, then the print dialog is tab modal, and the user
+  // can always close the tab on a mis-behaving page (the system print dialog
+  // is app modal). If the print was initiated through user action, don't
+  // throttle. Or, if the command line flag to skip throttling has been set.
+  if (!is_scripted_print_throttling_disabled_ &&
+      !is_preview_enabled_ &&
+      !user_initiated)
+    return !IsScriptInitiatedPrintTooFrequent(frame);
+  return true;
 }
 
 // Prints |frame| which called window.print().
-void PrintWebViewHelper::PrintPage(WebKit::WebFrame* frame) {
+void PrintWebViewHelper::PrintPage(WebKit::WebFrame* frame,
+                                   bool user_initiated) {
   DCHECK(frame);
 
   // Allow Prerendering to cancel this print request if necessary.
@@ -744,7 +759,7 @@ void PrintWebViewHelper::PrintPage(WebKit::WebFrame* frame) {
     return;
   }
 
-  if (!IsScriptInitiatedPrintAllowed(frame))
+  if (!IsScriptInitiatedPrintAllowed(frame, user_initiated))
     return;
   IncrementScriptedPrintCount();