Revive experiment to isolate shell operations.

chrome/common/shell_handler_win.mojom

Index: chrome/common/shell_handler_win.mojom
diff --git a/chrome/common/shell_handler_win.mojom b/chrome/common/shell_handler_win.mojom
index b16648d6064b4353ccc4c2c4bc34cc42f0268c46..84dd5949d1b85cf585f6557ee93fda008143aa9b 100644
--- a/chrome/common/shell_handler_win.mojom
+++ b/chrome/common/shell_handler_win.mojom
@@ -4,7 +4,20 @@
 
 module mojom;
 
+import "mojo/common/common_custom_types.mojom";
+
+[Native]
+struct FileExtensionFilters;
+
 interface ShellHandler {
   // Returns the pinned state of the current executable.
   IsPinnedToTaskbar() => (bool succeeded, bool is_pinned_to_taskbar);
+
+  // Instructs the utility process to invoke GetOpenFileName. |owner| is the

[sky, 2016/07/08 15:28:20]

document what owner is, e.g. an HWND.

[Patrick Monette, 2016/07/08 19:36:10]

Done.

+  // parent of the modal dialog, |flags| are OFN_* flags. |filter| constrains the

[sky, 2016/07/08 15:28:21]

nit: < 80

[Patrick Monette, 2016/07/08 19:36:10]

Done. Any suggestions on the formatting? Maybe the formatter should be able to
handle mojom files :)

[sky, 2016/07/08 20:47:14]

I try to follow what I think git cl format would do. By that I mean a single
argument per line, wrapping at 80...

+  // user's file choices. |initial_directory| and |filename| select the directory
+  // to be displayed and the file to be initially selected.

[sky, 2016/07/08 15:28:21]

Document what the result is if the user cancels the selection.

[Patrick Monette, 2016/07/08 19:36:10]

Done.

+  DoGetOpenFileName(uint64 owner, uint32 flags, FileExtensionFilters filters, mojo.common.mojom.FilePath initial_directory, mojo.common.mojom.FilePath filename) => (mojo.common.mojom.FilePath directory, array<mojo.common.mojom.FilePath> files);
+
+  DoGetSaveFileName(uint64 owner, uint32 flags, FileExtensionFilters filters, uint32 one_based_filter_index, mojo.common.mojom.FilePath initial_directory, mojo.common.mojom.FilePath suggested_filename, mojo.common.mojom.FilePath default_extension) => (mojo.common.mojom.FilePath path, uint32 one_based_filter_index);

[sky, 2016/07/08 15:28:21]

Document what one_based_filter_index means.

[Patrick Monette, 2016/07/08 19:36:10]

Done.

 };