3 files changed, 11 insertions, 3 deletions
diff --git a/chrome/common/transport_dib.h b/chrome/common/transport_dib.h
index 6d137ff..c28d78d 100644
--- a/chrome/common/transport_dib.h
+++ b/chrome/common/transport_dib.h
@@ -142,6 +142,8 @@ class TransportDIB {
   Display* display_;  // connection to the X server
 #endif
   size_t size_;  // length, in bytes
+
+  DISALLOW_COPY_AND_ASSIGN(TransportDIB);
 };
 
 class MessageLoop;
diff --git a/chrome/common/transport_dib_linux.cc b/chrome/common/transport_dib_linux.cc
index d239da2..d3ffe69 100644
--- a/chrome/common/transport_dib_linux.cc
+++ b/chrome/common/transport_dib_linux.cc
@@ -45,7 +45,7 @@ TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
   if (shmkey == -1) {
     DLOG(ERROR) << "Failed to create SysV shared memory region"
                 << " errno:" << errno;
-    return false;
+    return NULL;
   }
 
   void* address = shmat(shmkey, NULL /* desired address */, 0 /* flags */);
@@ -54,7 +54,7 @@ TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
   // that the kernel will automatically clean it up for us.
   shmctl(shmkey, IPC_RMID, 0);
   if (address == kInvalidAddress)
-    return false;
+    return NULL;
 
   TransportDIB* dib = new TransportDIB;
 
diff --git a/chrome/plugin/webplugin_proxy.cc b/chrome/plugin/webplugin_proxy.cc
index 0e2e006..8a04650 100644
--- a/chrome/plugin/webplugin_proxy.cc
+++ b/chrome/plugin/webplugin_proxy.cc
@@ -636,7 +636,13 @@ void WebPluginProxy::SetWindowlessBuffer(
   int width = delegate_->GetRect().width();
   int height = delegate_->GetRect().height();
   windowless_dib_.reset(TransportDIB::Map(windowless_buffer));
-  windowless_canvas_.reset(windowless_dib_->GetPlatformCanvas(width, height));
+  if (windowless_dib_.get()) {
+    windowless_canvas_.reset(windowless_dib_->GetPlatformCanvas(width, height));
+  } else {
+    // This can happen if the renderer has already destroyed the TransportDIB
+    // by the time we receive the handle, e.g. in case of multiple resizes.
+    windowless_canvas_.reset();
+  }
   background_dib_.reset(TransportDIB::Map(background_buffer));
   if (background_dib_.get()) {
     background_canvas_.reset(background_dib_->GetPlatformCanvas(width, height));