From 1b8f76dd69386ac710832bc84fe97374c16ddc96 Mon Sep 17 00:00:00 2001
From: Marshall Greenblatt <magreenblatt@gmail.com>
Date: Mon, 29 Feb 2016 15:23:44 -0500
Subject: [PATCH] Fix thread safety issue with CefBrowserHostImpl::IsWindowless

---
 libcef/browser/browser_host_impl.cc | 63 +++++++++++++++--------------
 libcef/browser/browser_host_impl.h  |  1 +
 2 files changed, 33 insertions(+), 31 deletions(-)

diff --git a/libcef/browser/browser_host_impl.cc b/libcef/browser/browser_host_impl.cc
index 573eeeb43..1178a1c30 100644
--- a/libcef/browser/browser_host_impl.cc
+++ b/libcef/browser/browser_host_impl.cc
@@ -1259,7 +1259,7 @@ bool CefBrowserHostImpl::SendProcessMessage(
 // -----------------------------------------------------------------------------
 
 bool CefBrowserHostImpl::IsWindowless() const {
-  return platform_delegate_->IsWindowless();
+  return is_windowless_;
 }
 
 void CefBrowserHostImpl::WindowDestroyed() {
@@ -1725,6 +1725,11 @@ void CefBrowserHostImpl::HandleKeyEventAfterTextInputClient(
 void CefBrowserHostImpl::DragTargetDragEnter(CefRefPtr<CefDragData> drag_data,
     const CefMouseEvent& event,
     CefBrowserHost::DragOperationsMask allowed_ops) {
+  if (!IsWindowless()) {
+    NOTREACHED() << "Window rendering is not disabled";
+    return;
+  }
+
   if (!CEF_CURRENTLY_ON_UIT()) {
     CEF_POST_TASK(CEF_UIT,
         base::Bind(&CefBrowserHostImpl::DragTargetDragEnter, this, drag_data,
@@ -1737,11 +1742,6 @@ void CefBrowserHostImpl::DragTargetDragEnter(CefRefPtr<CefDragData> drag_data,
     return;
   }
 
-  if (!IsWindowless()) {
-    NOTREACHED() << "Window rendering is not disabled";
-    return;
-  }
-
   if (!web_contents())
     return;
 
@@ -1750,6 +1750,11 @@ void CefBrowserHostImpl::DragTargetDragEnter(CefRefPtr<CefDragData> drag_data,
 
 void CefBrowserHostImpl::DragTargetDragOver(const CefMouseEvent& event,
     CefBrowserHost::DragOperationsMask allowed_ops) {
+  if (!IsWindowless()) {
+    NOTREACHED() << "Window rendering is not disabled";
+    return;
+  }
+
   if (!CEF_CURRENTLY_ON_UIT()) {
     CEF_POST_TASK(CEF_UIT,
         base::Bind(&CefBrowserHostImpl::DragTargetDragOver, this, event,
@@ -1757,11 +1762,6 @@ void CefBrowserHostImpl::DragTargetDragOver(const CefMouseEvent& event,
     return;
   }
 
-  if (!IsWindowless()) {
-    NOTREACHED() << "Window rendering is not disabled";
-    return;
-  }
-
   if (!web_contents())
     return;
 
@@ -1769,14 +1769,14 @@ void CefBrowserHostImpl::DragTargetDragOver(const CefMouseEvent& event,
 }
 
 void CefBrowserHostImpl::DragTargetDragLeave() {
-  if (!CEF_CURRENTLY_ON_UIT()) {
-    CEF_POST_TASK(CEF_UIT,
-        base::Bind(&CefBrowserHostImpl::DragTargetDragLeave, this));
+  if (!IsWindowless()) {
+    NOTREACHED() << "Window rendering is not disabled";
     return;
   }
 
-  if (!IsWindowless()) {
-    NOTREACHED() << "Window rendering is not disabled";
+  if (!CEF_CURRENTLY_ON_UIT()) {
+    CEF_POST_TASK(CEF_UIT,
+        base::Bind(&CefBrowserHostImpl::DragTargetDragLeave, this));
     return;
   }
 
@@ -1787,14 +1787,14 @@ void CefBrowserHostImpl::DragTargetDragLeave() {
 }
 
 void CefBrowserHostImpl::DragTargetDrop(const CefMouseEvent& event) {
-  if (!CEF_CURRENTLY_ON_UIT()) {
-    CEF_POST_TASK(CEF_UIT,
-        base::Bind(&CefBrowserHostImpl::DragTargetDrop, this, event));
+  if (!IsWindowless()) {
+    NOTREACHED() << "Window rendering is not disabled";
     return;
   }
 
-  if (!IsWindowless()) {
-    NOTREACHED() << "Window rendering is not disabled";
+  if (!CEF_CURRENTLY_ON_UIT()) {
+    CEF_POST_TASK(CEF_UIT,
+        base::Bind(&CefBrowserHostImpl::DragTargetDrop, this, event));
     return;
   }
 
@@ -1805,14 +1805,14 @@ void CefBrowserHostImpl::DragTargetDrop(const CefMouseEvent& event) {
 }
 
 void CefBrowserHostImpl::DragSourceSystemDragEnded() {
-  if (!CEF_CURRENTLY_ON_UIT()) {
-    CEF_POST_TASK(CEF_UIT,
-        base::Bind(&CefBrowserHostImpl::DragSourceSystemDragEnded, this));
+  if (!IsWindowless()) {
+    NOTREACHED() << "Window rendering is not disabled";
     return;
   }
 
-  if (!IsWindowless()) {
-    NOTREACHED() << "Window rendering is not disabled";
+  if (!CEF_CURRENTLY_ON_UIT()) {
+    CEF_POST_TASK(CEF_UIT,
+        base::Bind(&CefBrowserHostImpl::DragSourceSystemDragEnded, this));
     return;
   }
 
@@ -1821,14 +1821,14 @@ void CefBrowserHostImpl::DragSourceSystemDragEnded() {
 
 void CefBrowserHostImpl::DragSourceEndedAt(
     int x, int y, CefBrowserHost::DragOperationsMask op) {
-  if (!CEF_CURRENTLY_ON_UIT()) {
-    CEF_POST_TASK(CEF_UIT,
-        base::Bind(&CefBrowserHostImpl::DragSourceEndedAt, this, x, y, op));
+  if (!IsWindowless()) {
+    NOTREACHED() << "Window rendering is not disabled";
     return;
   }
 
-  if (!IsWindowless()) {
-    NOTREACHED() << "Window rendering is not disabled";
+  if (!CEF_CURRENTLY_ON_UIT()) {
+    CEF_POST_TASK(CEF_UIT,
+        base::Bind(&CefBrowserHostImpl::DragSourceEndedAt, this, x, y, op));
     return;
   }
 
@@ -2638,6 +2638,7 @@ CefBrowserHostImpl::CefBrowserHostImpl(
       opener_(kNullWindowHandle),
       request_context_(request_context),
       platform_delegate_(std::move(platform_delegate)),
+      is_windowless_(platform_delegate_->IsWindowless()),
       is_loading_(false),
       can_go_back_(false),
       can_go_forward_(false),
diff --git a/libcef/browser/browser_host_impl.h b/libcef/browser/browser_host_impl.h
index f15a5a8af..45dddb144 100644
--- a/libcef/browser/browser_host_impl.h
+++ b/libcef/browser/browser_host_impl.h
@@ -520,6 +520,7 @@ class CefBrowserHostImpl : public CefBrowserHost,
   CefWindowHandle opener_;
   CefRefPtr<CefRequestContext> request_context_;
   scoped_ptr<CefBrowserPlatformDelegate> platform_delegate_;
+  const bool is_windowless_;
 
   // Volatile state information. All access must be protected by the state lock.
   base::Lock state_lock_;