Always call the class methods to save/restore contexts.

ui/base/clipboard/clipboard_mac.mm

Index: ui/base/clipboard/clipboard_mac.mm
diff --git a/ui/base/clipboard/clipboard_mac.mm b/ui/base/clipboard/clipboard_mac.mm
index 9f65e79e7c3f2e26c73d4ca72268a6d58c6f2a7f..bc8efede1c52d7e4cf793aa3e64ffec446a54a83 100644
--- a/ui/base/clipboard/clipboard_mac.mm
+++ b/ui/base/clipboard/clipboard_mac.mm
@@ -16,6 +16,7 @@
 #import "third_party/mozilla/NSPasteboard+Utils.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h"
 #include "ui/gfx/size.h"
 
 namespace ui {
@@ -248,6 +249,7 @@ SkBitmap Clipboard::ReadImage(Buffer buffer) const {
   scoped_nsobject<NSImage> image(
       [[NSImage alloc] initWithPasteboard:GetPasteboard()]);
   if (image.get()) {
+    gfx::ScopedNSGraphicsContextSaveGState scoped_state;
     [image setFlipped:YES];
     int width = [image size].width;
     int height = [image size].height;
@@ -262,7 +264,6 @@ SkBitmap Clipboard::ReadImage(Buffer buffer) const {
              fromRect:NSZeroRect
             operation:NSCompositeCopy
              fraction:1.0];
-    [NSGraphicsContext restoreGraphicsState];
     return canvas.ExtractBitmap();
   }
   return SkBitmap();