[Presentation API] Adding a flag to disable gesture check for starting presentations

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index b124c14d7bef8fbd1ced45a41bb5c842ec2bdb23..caa70a6aa50534d550b273cc16ac8f00bd58e88e 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -133,6 +133,10 @@ const char kDisableFlashStage3d[]           = "disable-flash-stage3d";
 const char kDisableGestureRequirementForMediaPlayback[] =
     "disable-gesture-requirement-for-media-playback";
 
+// Disable user gesture requirement for presentation.
+const char kDisableGestureRequirementForPresentation[] =
+    "disable-gesture-requirement-for-presentation";
+
 // Disables GPU hardware acceleration.  If software renderer is not in place,
 // then the GPU process won't launch.
 const char kDisableGpu[]                    = "disable-gpu";