Add support for Mac/iOS application bundles to GN tool.

build/toolchain/mac/BUILD.gn

Index: build/toolchain/mac/BUILD.gn
diff --git a/build/toolchain/mac/BUILD.gn b/build/toolchain/mac/BUILD.gn
index 2666846c19303dfb370b1e08a961705b3c234584..ecd740654a9450870a0f2aacb7e2a0144861a303 100644
--- a/build/toolchain/mac/BUILD.gn
+++ b/build/toolchain/mac/BUILD.gn
@@ -231,6 +231,10 @@ template("mac_toolchain") {
       command = copy_command
       description = copy_description
     }
+    tool("copy_bundle_data") {
+      command = "rm -rf {{output}} && ./gyp-mac-tool copy-bundle-resource {{source}} {{output}} True"

[brettw, 2016/01/20 22:23:17]

My understanding is that the source will be a single file and this will be
called once for every file in the bundle rule, and output is the directory.

As-written, it looks like this will clear the directory every time we add a new
file. If we want to clear the directory (and I think we do), we should probably
have a command that lists all input files and does the bundle copy in one step.

[sdefresne, 2016/01/21 22:00:56]

This is incorrect. This tool will be invoked for each file listed in
"bundle_data" independently, with {{output}} being a single file (as is done
with the "copy" tool). I could not simply re-use the "copy" tool as copying file
in the bundle may require some additional processing (conversion to binary for
.plist, ...).

[brettw, 2016/01/25 21:06:08]

I see, I see "rm -rf" and I assume the parameter is a directory. It looks like
the rm isn't even necessary? The normal copy command doesn't do this.

[sdefresne, 2016/01/26 12:11:54]

Replied on https://codereview.chromium.org/1611363003.

+      description = "COPY_BUNDLE_DATA {{source}} {{output}}"
+    }
 
     toolchain_args() {
       current_cpu = invoker.toolchain_cpu