Reset the default value of touch event flag back to "Auto".

chrome/test/ppapi/ppapi_test.cc

Index: chrome/test/ppapi/ppapi_test.cc
diff --git a/chrome/test/ppapi/ppapi_test.cc b/chrome/test/ppapi/ppapi_test.cc
index 250c0bc535ca6235b0f13f32e9349f83cd1b56b6..50b8efa75549db2c8a6c2c0e0b821ca552601c35 100644
--- a/chrome/test/ppapi/ppapi_test.cc
+++ b/chrome/test/ppapi/ppapi_test.cc
@@ -37,6 +37,7 @@
 #include "net/test/spawned_test_server/spawned_test_server.h"
 #include "net/test/test_data_directory.h"
 #include "ppapi/shared_impl/ppapi_switches.h"
+#include "ui/events/event_switches.h"
 #include "ui/gl/gl_switches.h"
 
 using content::RenderViewHost;
@@ -143,6 +144,9 @@ void PPAPITestBase::SetUpCommandLine(base::CommandLine* command_line) {
 
   // Smooth scrolling confuses the scrollbar test.
   command_line->AppendSwitch(switches::kDisableSmoothScrolling);
+
+  // Enable touche events api.

[raymes, 2016/11/30 02:14:41]

nit: touche->touch

[sunyunjia, 2016/11/30 02:41:53]

Done.

+  command_line->AppendSwitch(switches::kTouchEvents);

[raymes, 2016/11/30 02:14:41]

Hmm, how come this is needed?

[sunyunjia, 2016/11/30 02:41:53]

In the previous patch(https://codereview.chromium.org/2467913002), we prevent
the touch-actions in TouchEventManager based on the touch-events flag
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/input/Tou....
In that patch, we set the default value of the flag as "enabled" so there's no
problem.

In this patch, we reset the default value to "auto" depending on whether there's
a touchscreen, which is false in the test, and the test fails because of that.
So we want to manually set it as "enabled" to pass the test.

 }
 
 void PPAPITestBase::SetUpOnMainThread() {