Fixes stable build by including stringprintf.h
Fixes stable build by including stringprintf.h

stringprintf.h was included indirectly via:

chrome/browser/themes/theme_service.cc
 #include "chrome/browser/extensions/extension_service_test_base.h"
  #include "content/public/test/test_utils.h"
   #include "content/public/browser/web_contents_observer.h"
    #include "content/public/common/frame_navigate_params.h"
     #include "ipc/ipc_message_utils.h"
      #include "base/strings/stringprintf.h"

This CL should fix the branches that do not have this whole chain.

BUG=604059
NO_TRY=true
R=pkotwicz@chromium.org

Review URL: https://codereview.chromium.org/1891283003 .

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#387769}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk