Allow UI LatencyInfo types to be typemapped in blink.

Moving input handling into blink (from content) requires some additional
typemaps.

BUG=1073560

Change-Id: I5f58dbd11905a3195be1d31f442a963b8f0034f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2226312Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775135}

ui/latency/mojom/BUILD.gn

@@ -4,6 +4,20 @@
 
 import("//mojo/public/tools/bindings/mojom.gni")
 
+component("shared_mojom_traits") {
+  output_name = "latency_shared_mojom_traits"
+  defines = [ "IS_LATENCY_SHARED_MOJOM_TRAITS_IMPL" ]
+  sources = [
+    "latency_info_mojom_traits.cc",
+    "latency_info_mojom_traits.h",
+  ]
+  public_deps = [
+    ":mojom_shared",
+    "//ipc:param_traits",
+    "//ui/latency",
+  ]
+}
+
 mojom("mojom") {
   generate_java = true
   sources = [ "latency_info.mojom" ]
@@ -22,12 +36,14 @@ mojom("mojom") {
           cpp = "::ui::LatencyInfo"
         },
       ]
-      traits_sources = [ "latency_info_mojom_traits.cc" ]
       traits_headers = [ "latency_info_mojom_traits.h" ]
-      traits_public_deps = [ "//ui/latency" ]
-      traits_deps = [ "//ipc:param_traits" ]
+      traits_public_deps = [
+        ":shared_mojom_traits",
+        "//ui/latency",
+      ]
     },
   ]
+  blink_cpp_typemaps = cpp_typemaps
 }
 
 mojom("test_interfaces") {

ui/latency/mojom/latency_info_mojom_traits.h

@@ -5,6 +5,7 @@
 #ifndef UI_LATENCY_MOJOM_LATENCY_INFO_MOJOM_TRAITS_H_
 #define UI_LATENCY_MOJOM_LATENCY_INFO_MOJOM_TRAITS_H_
 
+#include "base/component_export.h"
 #include "ui/latency/latency_info.h"
 #include "ui/latency/mojom/latency_info.mojom-shared.h"
 
@@ -19,7 +20,8 @@ static_assert(static_cast<int>(ui::mojom::SourceEventType::kMaxValue) ==
               "Enum size mismatch");
 
 template <>
-struct ArrayTraits<ui::LatencyInfo::LatencyMap> {
+struct COMPONENT_EXPORT(LATENCY_SHARED_MOJOM_TRAITS)
+    ArrayTraits<ui::LatencyInfo::LatencyMap> {
   using Element = ui::LatencyInfo::LatencyMap::value_type;
   using Iterator = ui::LatencyInfo::LatencyMap::iterator;
   using ConstIterator = ui::LatencyInfo::LatencyMap::const_iterator;
@@ -43,7 +45,8 @@ struct ArrayTraits<ui::LatencyInfo::LatencyMap> {
 };
 
 template <>
-struct StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo> {
+struct COMPONENT_EXPORT(LATENCY_SHARED_MOJOM_TRAITS)
+    StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo> {
   static const ui::LatencyInfo::LatencyMap& latency_components(
       const ui::LatencyInfo& info);
   static int64_t trace_id(const ui::LatencyInfo& info);
@@ -60,7 +63,8 @@ struct StructTraits<ui::mojom::LatencyInfoDataView, ui::LatencyInfo> {
 };
 
 template <>
-struct EnumTraits<ui::mojom::LatencyComponentType, ui::LatencyComponentType> {
+struct COMPONENT_EXPORT(LATENCY_SHARED_MOJOM_TRAITS)
+    EnumTraits<ui::mojom::LatencyComponentType, ui::LatencyComponentType> {
   static ui::mojom::LatencyComponentType ToMojom(ui::LatencyComponentType type);
   static bool FromMojom(ui::mojom::LatencyComponentType input,
                         ui::LatencyComponentType* output);