Add Equals() to mojom structs and related types.

mojo/public/cpp/bindings/struct_ptr.h

Index: mojo/public/cpp/bindings/struct_ptr.h
diff --git a/mojo/public/cpp/bindings/struct_ptr.h b/mojo/public/cpp/bindings/struct_ptr.h
index 5d0836489aadfda523cae11266bbb0793057d270..c13c8863d121c639f63e26b12222795de85424cb 100644
--- a/mojo/public/cpp/bindings/struct_ptr.h
+++ b/mojo/public/cpp/bindings/struct_ptr.h
@@ -71,6 +71,12 @@ class StructPtr {
   // that it contains Mojo handles).
   StructPtr Clone() const { return is_null() ? StructPtr() : ptr_->Clone(); }
 
+  bool Equals(const StructPtr& other) const {
+    if (is_null() != other.is_null())
+      return false;
+    return ptr_->Equals(*other.ptr_);

[yzshen1, 2014/10/14 21:47:21]

ptr_ and other.ptr_ may both be null here. (Please consider a test case for
this. :))

[Aaron Boodman, 2014/10/14 22:30:12]

Good point! Thanks.

+  }
+
  private:
   typedef Struct* StructPtr::*Testable;
 
@@ -139,6 +145,11 @@ class InlinedStructPtr {
   InlinedStructPtr Clone() const {
     return is_null() ? InlinedStructPtr() : value_.Clone();
   }
+  bool Equals(const InlinedStructPtr& other) const {
+    if (is_null() != other.is_null())
+      return false;
+    return value_.Equals(other.value_);

[yzshen1, 2014/10/14 21:47:21]

It seems we don't need to compare the value if they are both null.

[Aaron Boodman, 2014/10/14 22:30:12]

Done.

+  }
 
  private:
   typedef Struct InlinedStructPtr::*Testable;