Only build various flash/pnacl/ppapi code when they are enabled. (try 2)

Review URL: https://codereview.chromium.org/494993005

Cr-Commit-Position: refs/heads/master@{#291810}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index d021820..f170292 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -168,7 +168,6 @@
       "//mojo/system",
       "//net:net_with_v8",
       "//third_party/WebKit/public:resources",
-      "//third_party/adobe/flash:flapper_version_h",
       "//third_party/expat",
       "//third_party/leveldatabase",
       "//third_party/libaddressinput",
@@ -306,6 +305,7 @@
                            ".", "//chrome")
     deps += [
       "//ppapi:ppapi_ipc",
+      "//third_party/adobe/flash:flapper_version_h",
     ]
   }
   if (safe_browsing_mode != 0) {