Add an UMA metric to track whether chrome is running on a tablet.

base/win/win_util.cc

Index: base/win/win_util.cc
diff --git a/base/win/win_util.cc b/base/win/win_util.cc
index 601dd7cd28847e1facb06d26b66f4952335124d0..358751261c4c26664cd33317286a7dbaee56a007 100644
--- a/base/win/win_util.cc
+++ b/base/win/win_util.cc
@@ -6,6 +6,7 @@
 
 #include <aclapi.h>
 #include <lm.h>
+#include <powrprof.h>
 #include <shellapi.h>
 #include <shlobj.h>
 #include <shobjidl.h>  // Must be before propkey.
@@ -232,6 +233,34 @@ bool IsTouchEnabledDevice() {
   return false;
 }
 
+bool IsTabletDevice() {
+  if (GetSystemMetrics(SM_MAXIMUMTOUCHES) == 0)
+    return false;
+
+  base::win::Version version = base::win::GetVersion();
+  if (version == base::win::VERSION_XP)
+    return (GetSystemMetrics(SM_TABLETPC) != 0);
+
+  // If the device is docked, the user is treating the device as a PC.
+  if (GetSystemMetrics(SM_SYSTEMDOCKED) != 0)
+    return false;
+
+  // PlatformRoleSlate was only added in Windows 8, but prior to Win8 it is
+  // still possible to check for a mobile power profile.
+  bool has_tablet_power_profile = false;

[cpu_(ooo_6.6-7.5), 2014/05/06 19:48:45]

seems we can init has_table_power_profile in line 252

+  POWER_PLATFORM_ROLE role = PowerDeterminePlatformRole();
+  has_tablet_power_profile = (role == PlatformRoleMobile);
+  if (version >= base::win::VERSION_WIN8)
+    has_tablet_power_profile |= (role == PlatformRoleSlate);

[cpu_(ooo_6.6-7.5), 2014/05/06 19:48:45]

the bitwise or scares me. Can you change to good ol || ?

+
+  if (has_tablet_power_profile) {
+    bool slate_mode = (GetSystemMetrics(SM_CONVERTIBLESLATEMODE) == 0);
+    return slate_mode;
+  }
+
+  return false;
+}
+
 bool DisplayVirtualKeyboard() {
   if (base::win::GetVersion() < base::win::VERSION_WIN8)
     return false;