Resize only the virtual viewport when the OSK triggers a resize.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 09ba9415359f77552d6bd72ed17cfcf087385863..24f6ffd3c2a1bb509bcd47094bf127f8824beede 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -621,6 +621,11 @@ const FeatureEntry kFeatureEntries[] = {
     {"disable-webaudio", IDS_FLAGS_WEBAUDIO_NAME,
      IDS_FLAGS_WEBAUDIO_DESCRIPTION, kOsAndroid,
      SINGLE_DISABLE_VALUE_TYPE(switches::kDisableWebAudio)},
+    {"enable-osk-overscroll",
+     IDS_FLAGS_ENABLE_OSK_OVERSCROLL_NAME,
+     IDS_FLAGS_ENABLE_OSK_OVERSCROLL_DESCRIPTION,
+     kOsAndroid,
+     SINGLE_VALUE_TYPE(switches::kEnableOSKOverscroll)},
 #endif
   // Native client is compiled out when DISABLE_NACL is defined.
 #if !defined(DISABLE_NACL)