platform2: Move Error class from Buffet to libchromeos

Moved buffet::Error class and related facilities to
libchromeos and changed the namespace to 'chromeos::'.
Updated a bunch of code to include the header files
from the new location and referring to the new
namespace.

BUG=chromium:403604
TEST=USE=buffet ./build_packages
     FEATURES=test emerge-link libchromeos
     USE=buffet FEATURES=test emerge-link platform2

Change-Id: I0b5b37ccd7ee3b7be9467ebfae5d172d9b057cf6
Reviewed-on: https://chromium-review.googlesource.com/212525
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/commands/schema_utils_unittest.cc b/buffet/commands/schema_utils_unittest.cc
index e20532d..1a92d7f 100644
--- a/buffet/commands/schema_utils_unittest.cc
+++ b/buffet/commands/schema_utils_unittest.cc
@@ -73,7 +73,7 @@
                                          &value, nullptr));
   EXPECT_FALSE(value);
 
-  buffet::ErrorPtr error;
+  chromeos::ErrorPtr error;
   EXPECT_FALSE(buffet::TypedValueFromJson(CreateValue("0").get(), nullptr,
                                           &value, &error));
   EXPECT_EQ("type_mismatch", error->GetCode());
@@ -95,7 +95,7 @@
                                          &value, nullptr));
   EXPECT_EQ(-1234, value);
 
-  buffet::ErrorPtr error;
+  chromeos::ErrorPtr error;
   EXPECT_FALSE(buffet::TypedValueFromJson(CreateValue("'abc'").get(), nullptr,
                                           &value, &error));
   EXPECT_EQ("type_mismatch", error->GetCode());
@@ -123,7 +123,7 @@
                                          nullptr, &value, nullptr));
   EXPECT_EQ(-123.0, value);
 
-  buffet::ErrorPtr error;
+  chromeos::ErrorPtr error;
   EXPECT_FALSE(buffet::TypedValueFromJson(CreateValue("'abc'").get(), nullptr,
                                           &value, &error));
   EXPECT_EQ("type_mismatch", error->GetCode());
@@ -145,7 +145,7 @@
                                          &value, nullptr));
   EXPECT_EQ("abc", value);
 
-  buffet::ErrorPtr error;
+  chromeos::ErrorPtr error;
   EXPECT_FALSE(buffet::TypedValueFromJson(CreateValue("12").get(), nullptr,
                                           &value, &error));
   EXPECT_EQ("type_mismatch", error->GetCode());
@@ -172,7 +172,7 @@
                                name_prop->CreateValue(std::string("Bob"))));
   EXPECT_EQ(value2, value);
 
-  buffet::ErrorPtr error;
+  chromeos::ErrorPtr error;
   EXPECT_FALSE(buffet::TypedValueFromJson(CreateValue("'abc'").get(), nullptr,
                                           &value, &error));
   EXPECT_EQ("type_mismatch", error->GetCode());