Support explicit pools in actions

tools/gn/variables.cc

Index: tools/gn/variables.cc
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index d304bc508cfef300b8b81c6378286b49caed22c9..9adae8b10ed3e7ebea407e075a55678e68ff8438 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -929,13 +929,13 @@ Example
 
 const char kConsole[] = "console";
 const char kConsole_HelpShort[] =
-    "console: [boolean] Run this action in the console pool.";
+    "console: [boolean] Use console pool for the pool object.";
 const char kConsole_Help[] =
-    R"(console: Run this action in the console pool.
+    R"(console: Use console pool for the pool object.
 
   Boolean. Defaults to false.
 
-  Actions marked "console = true" will be run in the built-in ninja "console"
+  Pool objects marked "console = true" will use the built-in ninja "console"
   pool. They will have access to real stdin and stdout, and output will not be
   buffered by ninja. This can be useful for long-running actions with progress
   logs, or actions that require user input.
@@ -945,7 +945,7 @@ const char kConsole_Help[] =
 
 Example
 
-  action("long_action_with_progress_logs") {
+  pool("action_pool") {
     console = true
   }
 )";
@@ -1441,6 +1441,23 @@ const char kOutputs_Help[] =
     with no source expansions. See "gn help action".
 )";
 
+const char kPool[] = "pool";

[brettw, 2017/06/13 21:59:16]

Did you have any thouhgs on how to fix the "gn help" issue for this?

[Petr Hosek, 2017/06/17 02:44:25]

I tried to modify help command to handle the case where the same topic is
defined for functions and variables and it doesn't look too terrible, what do
you think?

+const char kPool_HelpShort[] =
+    "pool: [string] Label of the pool used by the action.";
+const char kPool_Help[] =
+    R"(pool: Label of the pool used by the action.
+
+  A fully-qualified label representing the pool that will be used for the
+  action. Pools are defined using the pool() {...} declaration.
+
+Example
+
+  action("action") {
+    pool = "//build:custom_pool"
+    ...
+  }
+)";
+
 const char kPrecompiledHeader[] = "precompiled_header";
 const char kPrecompiledHeader_HelpShort[] =
     "precompiled_header: [string] Header file to precompile.";