Add CFX_RenderDevice::AutoRestorer()chromium/3078

Avoid cleanup on every return path.

Change-Id: I6978adb6f31020d812ac88c5d46c703d1461d373
Reviewed-on: https://pdfium-review.googlesource.com/4435
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/core/fxge/cfx_renderdevice.h b/core/fxge/cfx_renderdevice.h
index 794c2fec6b..6aa4528f05 100644
--- a/core/fxge/cfx_renderdevice.h
+++ b/core/fxge/cfx_renderdevice.h
@@ -83,6 +83,17 @@ class FXTEXT_CHARPOS {
 
 class CFX_RenderDevice {
  public:
+  class StateRestorer {
+   public:
+    explicit StateRestorer(CFX_RenderDevice* pDevice) : m_pDevice(pDevice) {
+      m_pDevice->SaveState();
+    }
+    ~StateRestorer() { m_pDevice->RestoreState(false); }
+
+   private:
+    CFX_RenderDevice* m_pDevice;
+  };
+
   CFX_RenderDevice();
   virtual ~CFX_RenderDevice();