Add --content-shell-host-window-size switch to control the window size for content_shell.

content/shell/common/shell_switches.cc

Index: content/shell/common/shell_switches.cc
diff --git a/content/shell/common/shell_switches.cc b/content/shell/common/shell_switches.cc
index e7d14f37ff3d339df7953490a4c6d528b9b7d3e2..6a7a48bd5e57b62f21bf2baae63f75f92fc0f620 100644
--- a/content/shell/common/shell_switches.cc
+++ b/content/shell/common/shell_switches.cc
@@ -59,4 +59,7 @@ const char kRegisterFontFiles[] = "register-font-files";
 // http://dev.chromium.org/blink/runtime-enabled-features.
 const char kStableReleaseMode[] = "stable-release-mode";
 
+// Size for the content_shell's host window (i.e. "800x600").
+const char kContentShellHostWindowSize[] = "content-shell-host-window-size";
+
 }  // namespace switches