Add tablet heuristic detection

Useful for win8 metro launching

BUG=141032
TEST=see bug
Review URL: https://chromiumcodereview.appspot.com/10909206

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@156589 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 15 insertions, 0 deletions

diff --git a/base/win/win_util.cc b/base/win/win_util.cc
index 37aae27..569de06 100644
--- a/base/win/win_util.cc
+++ b/base/win/win_util.cc
@@ -218,6 +218,16 @@ bool ShouldCrashOnProcessDetach() {
   return g_crash_on_process_detach;
 }
 
+bool IsMachineATablet() {
+  if (base::win::GetVersion() < base::win::VERSION_WIN7)
+    return false;
+  // TODO(ananta): Add keyboard detection logic if it can be made reliable.
+  const int kPenInput = NID_INTEGRATED_PEN | NID_EXTERNAL_PEN;
+  const int kMultiTouch = NID_INTEGRATED_TOUCH | NID_MULTI_INPUT | NID_READY;
+  int sm = GetSystemMetrics(SM_DIGITIZER);
+  return ((sm & kMultiTouch) == kMultiTouch) && ((sm & kPenInput) == 0);
+}
+
 }  // namespace win
 }  // namespace base
 
diff --git a/base/win/win_util.h b/base/win/win_util.h
index 51dfbd6..5a5a20a 100644
--- a/base/win/win_util.h
+++ b/base/win/win_util.h
@@ -105,6 +105,11 @@ BASE_EXPORT bool ReadCommandFromAutoRun(HKEY root_key,
 BASE_EXPORT void SetShouldCrashOnProcessDetach(bool crash);
 BASE_EXPORT bool ShouldCrashOnProcessDetach();
 
+// A tablet by this definition is something that has integrated multi-touch
+// but is not also pen-enabled. For example a Thinkpad X220 tablet is not
+// considered a tabled while a Samsum 700T tablet is.
+BASE_EXPORT bool IsMachineATablet();
+
 // Get the size of a struct up to and including the specified member.
 // This is necessary to set compatible struct sizes for different versions
 // of certain Windows APIs (e.g. SystemParametersInfo).