extensions: Add CPU temperatures field to system.cpu.getInfo() function

extensions/browser/api/system_cpu/system_cpu_apitest.cc

Index: extensions/browser/api/system_cpu/system_cpu_apitest.cc
diff --git a/extensions/browser/api/system_cpu/system_cpu_apitest.cc b/extensions/browser/api/system_cpu/system_cpu_apitest.cc
index eabacff9393df97dbea45bf326e9ab95bf9df720..5685db52ec3a74c4346dfd0df81472032c15be23 100644
--- a/extensions/browser/api/system_cpu/system_cpu_apitest.cc
+++ b/extensions/browser/api/system_cpu/system_cpu_apitest.cc
@@ -28,6 +28,10 @@ class MockCpuInfoProviderImpl : public CpuInfoProvider {
     info_.processors[0].usage.user = 2;
     info_.processors[0].usage.idle = 3;
     info_.processors[0].usage.total = 6;
+
+    // The fractional part of these values should be exactly represented as
+    // floating points to avoid rounding errors.
+    info_.temperatures = {30.125, 40.0625};
     return true;
   }