Add --dump-line-box-trees parameter to content_shell.

content/shell/browser/shell_content_browser_client.cc

Index: content/shell/browser/shell_content_browser_client.cc
diff --git a/content/shell/browser/shell_content_browser_client.cc b/content/shell/browser/shell_content_browser_client.cc
index ab722f4b0c009ee804865095f42055a51388b751..1c40bc34328218c78f405d389f51cac9c4714a65 100644
--- a/content/shell/browser/shell_content_browser_client.cc
+++ b/content/shell/browser/shell_content_browser_client.cc
@@ -229,6 +229,9 @@ void ShellContentBrowserClient::AppendExtraCommandLineSwitches(
           switches::kRunLayoutTest))
     command_line->AppendSwitch(switches::kRunLayoutTest);
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDumpLineBoxTrees))

[Mike West, 2015/06/12 07:27:22]

Style nit: All of these multi-line `if` statements need brackets. I don't know
why they don't; since you're here, would you mind either fixing them in this
patch, or submitting a separate patch to add `{}`?

+    command_line->AppendSwitch(switches::kDumpLineBoxTrees);
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableFontAntialiasing))
     command_line->AppendSwitch(switches::kEnableFontAntialiasing);
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(