Add a command line switch to control the window size of content_shell.

This CL introduces a command line switch "--content-shell-host-window-size" to help the developers to specify the content_shell size for windowless ozone platforms like test, egltest, dri, caca.

Prior to this CL, the developer has to change the constants(kDefaultTestWindowWidthDip, kDefaultTestWindowHeightDip) in shell.cc to increase the content_shell resolution for above mentioned ozone platforms.

Review URL: https://codereview.chromium.org/783203002

Cr-Commit-Position: refs/heads/master@{#308391}

content/shell/browser/shell.cc

@@ -39,6 +39,26 @@ base::Callback<void(Shell*)> Shell::shell_created_callback_;
 
 bool Shell::quit_message_loop_ = true;
 
+namespace {
+gfx::Size ShellDefaultSize() {
+  static gfx::Size default_shell_size;
+  if (!default_shell_size.IsEmpty())
+    return default_shell_size;
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kContentShellHostWindowSize)) {
+    const std::string size_str = command_line->GetSwitchValueASCII(
+                  switches::kContentShellHostWindowSize);
+    int width, height;
+    CHECK_EQ(2, sscanf(size_str.c_str(), "%dx%d", &width, &height));
+    default_shell_size = gfx::Size(width, height);
+  } else {
+    default_shell_size = gfx::Size(
+      Shell::kDefaultTestWindowWidthDip, Shell::kDefaultTestWindowHeightDip);
+  }
+  return default_shell_size;
+}
+}  // namespace
+
 class Shell::DevToolsWebContentsObserver : public WebContentsObserver {
  public:
   DevToolsWebContentsObserver(Shell* shell, WebContents* web_contents)
@@ -141,14 +161,13 @@ Shell* Shell::FromRenderViewHost(RenderViewHost* rvh) {
 
 // static
 void Shell::Initialize() {
-  PlatformInitialize(
-      gfx::Size(kDefaultTestWindowWidthDip, kDefaultTestWindowHeightDip));
+  PlatformInitialize(ShellDefaultSize());
 }
 
 gfx::Size Shell::AdjustWindowSize(const gfx::Size& initial_size) {
   if (!initial_size.IsEmpty())
     return initial_size;
-  return gfx::Size(kDefaultTestWindowWidthDip, kDefaultTestWindowHeightDip);
+  return ShellDefaultSize();
 }
 
 Shell* Shell::CreateNewWindow(BrowserContext* browser_context,

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

content/shell/common/shell_switches.h

@@ -24,6 +24,7 @@ extern const char kEncodeBinary[];
 extern const char kExposeInternalsForTesting[];
 extern const char kRegisterFontFiles[];
 extern const char kStableReleaseMode[];
+extern const char kContentShellHostWindowSize[];
 
 }  // namespace switches