Make pinch-zoom work for OOP PDF

extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc

Index: extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
diff --git a/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc b/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
index 8f10a0be9f6ce20c82d479e82d7e95323bf4f407..b829c9e9106e25e87083267a5e83e98b91816bc4 100644
--- a/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
+++ b/extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
@@ -26,6 +26,7 @@
 #include "extensions/strings/grit/extensions_strings.h"
 #include "ipc/ipc_message_macros.h"
 #include "net/base/url_util.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 
 using content::WebContents;
 
@@ -187,6 +188,19 @@ bool MimeHandlerViewGuest::HandleContextMenu(
   return false;
 }
 
+bool MimeHandlerViewGuest::PreHandleGestureEvent(
+    content::WebContents* source,
+    const blink::WebGestureEvent& event) {
+  if (event.type == blink::WebGestureEvent::GesturePinchBegin ||
+      event.type == blink::WebGestureEvent::GesturePinchUpdate ||
+      event.type == blink::WebGestureEvent::GesturePinchEnd) {
+    // If we're an embedded plugin we drop pinch-gestures to avoid zooming the
+    // guest.
+    return !is_full_page_plugin();
+  }
+  return false;
+}
+
 void MimeHandlerViewGuest::FindReply(content::WebContents* web_contents,
                                      int request_id,
                                      int number_of_matches,