Revert of Remove DCHECK_IMPLIES/CHECK_IMPLIES.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index bc4f13dfec2cc29cba969d99242e2a79bb724f04..059e2b9e72775815ced7079c24b5ec767a3c3a9a 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -671,7 +671,7 @@
     RenderFrameHostImpl* render_frame_host,
     bool was_caused_by_user_gesture) {
   if (!pending_render_frame_host_ && !speculative_render_frame_host_) {
-    DCHECK(!should_reuse_web_ui_ || web_ui_);
+    DCHECK_IMPLIES(should_reuse_web_ui_, web_ui_);
 
     // We should only hear this from our current renderer.
     DCHECK_EQ(render_frame_host_, render_frame_host);
@@ -1770,12 +1770,12 @@
       SiteIsolationPolicy::IsSwappedOutStateForbidden();
 
   CHECK(instance);
-  CHECK(!swapped_out_forbidden || !swapped_out);
-  CHECK(SiteIsolationPolicy::AreCrossProcessFramesPossible() ||
-        frame_tree_node_->IsMainFrame());
+  CHECK_IMPLIES(swapped_out_forbidden, !swapped_out);
+  CHECK_IMPLIES(!SiteIsolationPolicy::AreCrossProcessFramesPossible(),
+                frame_tree_node_->IsMainFrame());
 
   // Swapped out views should always be hidden.
-  DCHECK(!swapped_out || (flags & CREATE_RF_HIDDEN));
+  DCHECK_IMPLIES(swapped_out, (flags & CREATE_RF_HIDDEN));
 
   scoped_ptr<RenderFrameHostImpl> new_render_frame_host;
   bool success = true;