Re-enable in-browser thumbnailing for Linux and Chrome OS.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index d14ce1445d2ec7a4eaab6f9a60e5c249975615ee..705e08adc3fabb2e503f40aa8ad1f5b08b1f7459 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -1179,8 +1179,13 @@ bool IsPrintPreviewEnabled() {
 #endif
 
 bool IsInBrowserThumbnailingEnabled() {
+#if defined(OS_LINUX) || defined(OS_CHROMEOS)
+  // The in-browser-thumbnailing is enabled for Linux and Chrome OS.
+  return true;
+#else
   return CommandLine::ForCurrentProcess()->HasSwitch(
       kEnableInBrowserThumbnailing);
+#endif
 }
 
 // -----------------------------------------------------------------------------