aw: Use comparison DCHECKs where appropriate

android_webview/browser/aw_browser_context.cc

Index: android_webview/browser/aw_browser_context.cc
diff --git a/android_webview/browser/aw_browser_context.cc b/android_webview/browser/aw_browser_context.cc
index 4287b02514445696ed74f8dba84bf9ef92daf4de..93650857e82a43dcfdc29c9bfa0bd5042488080c 100644
--- a/android_webview/browser/aw_browser_context.cc
+++ b/android_webview/browser/aw_browser_context.cc
@@ -52,7 +52,7 @@ AwBrowserContext::AwBrowserContext(
     JniDependencyFactory* native_factory)
     : context_storage_path_(path),
       native_factory_(native_factory) {
-  DCHECK(g_browser_context == NULL);
+  DCHECK(!g_browser_context);
   g_browser_context = this;
 
   // This constructor is entered during the creation of ContentBrowserClient,
@@ -61,7 +61,7 @@ AwBrowserContext::AwBrowserContext(
 }
 
 AwBrowserContext::~AwBrowserContext() {
-  DCHECK(g_browser_context == this);
+  DCHECK_EQ(this, g_browser_context);
   g_browser_context = NULL;
 }