A few weeks ago I started using Chrome on Mac OS X as my main Web browser. I had grown tired of Safari 4 chewing up nearly a gig of RAM after leaving it open for a week or more. Don't get me wrong, Safari is a fantastic browser and I wasn't happy about switching. But I can't have any browser chew through a gig of memory even if it takes it a week to do so. Chrome is nearly as fast as Safari (for me) and I've left it open for two weeks without any tab hogging memory. Each opened tab spawns its own process allowing a single tab to fail without affecting other tabs. In general I've found each tab occupies 25 MB to 40 MB of RAM. If you do that math you'll realize I can open around 25-40 tabs before Chrome takes up a gig of RAM.
Enough about my reasons for switching to Chrome, this post is about the Flash Player running in Chrome.
When I switched to Chrome I quickly realized the debugger version of the Flash Player wasn't being used. When I attempted to run a step debugging process Flash Builder 4 displayed a notification warning me I wasn't running a debugger version of the player. I validated this claim using Adobe's Flash Player version checker.
This seemed really odd to me since I knew I was running a debug version of the player. I launched Safari and loaded the Flash Player version checker and it said I was running the debug version. So I checked in Firefox and received the same result. Why was Safari and Firefox using a debugger player but Chrome wasn't. As far as I understood things every browser on OS X looked in the /Library/Internet Plug-ins/ for two files: Flash Player.plugin and flashplayer.xpt. Whichever versions of these files you had in the directory dictated your installed Flash Player version.
That's when I remembered Chrome has its own embedded version of Flash Player and it manages this version of the player without input from you. This is good and bad. Casual Chrome users receive automatic updates to the Flash Player which can be useful when there are critical Flash Player security updates. For programmers writing software for the Flash Player this feature isn't so good.
I dug through Chrome preferences and found the screen at Preferences - Under the Hood - Content Settings (button) - Plugins - Disable individual plug-ins (text). A faster way to get to this configuration screen is to enter chrome://plugins/ in your address bar. After disabling the default Chrome-managed version of Flash Player the Adobe Flash Player version checker reported the correct debugger version. I was now able to debug Flex applications in Flash Builder 4, though it still told me I wasn't running a debugger player.
For those who wind up disabling the default player like I did, be warned. Chrome automatically updates it's default Flash Player and when it does the plugin is re-enabled. And since the plugin is listed higher on the Plugins page, this version of the plugin takes precedence when two different versions are enabled. You may want to check from time to time to verify you are still running a debug version. Just today I had to disable the default plugin again.