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

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 dd4298b62cc145445dfbfb6d07c6e5bdc8ab5d5a..58610b0d06383f414bdba13339184318286773e2 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -950,6 +950,9 @@ const char kRendererWaitForJavaDebugger[] = "renderer-wait-for-java-debugger";
 // Maintaining this code path in case there are compatibility bugs with the
 // standard async input path. Remove tracked as part of crbug.com/545628.
 const char kSyncInputForSyncCompositor[]    = "sync-input-for-sync-compositor";
+
+// Enables overscrolling for the OSK on Android.
+const char kEnableOSKOverscroll[]               = "enable-osk-overscroll";
 #endif
 
 // Enable the aggressive flushing of DOM Storage to minimize data loss.